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Search: a081341 -id:a081341
Displaying 1-10 of 12 results found. page 1 2
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A055372 Invert transform of Pascal's triangle A007318. +10
14
1, 1, 1, 2, 4, 2, 4, 12, 12, 4, 8, 32, 48, 32, 8, 16, 80, 160, 160, 80, 16, 32, 192, 480, 640, 480, 192, 32, 64, 448, 1344, 2240, 2240, 1344, 448, 64, 128, 1024, 3584, 7168, 8960, 7168, 3584, 1024, 128, 256, 2304, 9216, 21504, 32256, 32256, 21504, 9216, 2304, 256 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,4
COMMENTS
Triangle T(n,k), 0 <= k <= n, read by rows, given by [1, 1, 0, 0, 0, 0, 0, 0, 0, ...] DELTA [1, 1, 0, 0, 0, 0, 0, 0, 0, ...] where DELTA is the operator defined in A084938. - Philippe Deléham, Aug 10 2005
T(n,k) is the number of nonempty bit strings with n bits and exactly k 1's over all strings in the sequence. For example, T(2,1)=4 because we have {(01)},{(10)},{(0),(1)},{(1),(0)}. - Geoffrey Critzer, Apr 06 2013
LINKS
N. J. A. Sloane, Transforms
FORMULA
a(n,k) = 2^(n-1)*C(n, k), for n>0.
G.f.: A(x, y)=(1-x-xy)/(1-2x-2xy).
As an infinite lower triangular matrix, equals A134309 * A007318. - Gary W. Adamson, Oct 19 2007
Sum_{k=0..n} T(n,k)*x^k = A000007(n), A011782(n), A081294(n), A081341(n), A092811(n), A093143(n), A067419(n) for x = -1, 0, 1, 2, 3, 4, 5 respectively. - Philippe Deléham, Feb 05 2012
EXAMPLE
Triangle begins:
1;
1, 1;
2, 4, 2;
4, 12, 12, 4;
8, 32, 48, 32, 8;
...
MATHEMATICA
nn=10; f[list_]:=Select[list, #>0&]; a=(x+y x)/(1-(x+y x)); Map[f, CoefficientList[Series[1/(1-a), {x, 0, nn}], {x, y}]]//Grid (* Geoffrey Critzer, Apr 06 2013 *)
CROSSREFS
Row sums give A081294. Cf. A000079, A007318, A055373, A055374.
Cf. A134309.
T(2n,n) gives A098402.
KEYWORD
nonn,tabl
AUTHOR
Christian G. Bower, May 16 2000
STATUS
approved
A134309 Triangle read by rows, where row n consists of n zeros followed by 2^(n-1). +10
14
1, 0, 1, 0, 0, 2, 0, 0, 0, 4, 0, 0, 0, 0, 8, 0, 0, 0, 0, 0, 16, 0, 0, 0, 0, 0, 0, 32, 0, 0, 0, 0, 0, 0, 0, 64, 0, 0, 0, 0, 0, 0, 0, 0, 128, 0, 0, 0, 0, 0, 0, 0, 0, 0, 256, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 512, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 1024, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 2048, 0, 0, 0, 0, 0, 0, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,6
COMMENTS
As infinite lower triangular matrices, binomial transform of A134309 = A082137. A134309 * A007318 = A055372. A134309 * [1,2,3,...] = A057711: (1, 2, 6, 16, 40, 96, 224,...).
Triangle read by rows given by [0,0,0,0,0,0,0,0,...] DELTA [1,1,0,0,0,0,0,0,0,...] where DELTA is the operator defined in A084938. - Philippe Deléham, Oct 20 2007
LINKS
FORMULA
Triangle, T(0,0) = 1, then for n > 0, n zeros followed by 2^(n-1). Infinite lower triangular matrix with (1, 1, 2, 4, 8, 16, ...) in the main diagonal and the rest zeros.
G.f.: (1 - y*x)/(1 - 2*y*x). - Philippe Deléham, Feb 04 2012
Sum_{k=0..n} T(n,k)*x^k = A000007(n), A011782(n), A081294(n), A081341(n), A092811(n), A093143(n), A067419(n) for x = 0, 1, 2, 3, 4, 5, 6 respectively. - Philippe Deléham, Feb 04 2012
Diagonal is A011782, other elements are 0. - M. F. Hasler, Mar 29 2022
EXAMPLE
Triangle T(n,k) (with rows n >= 0 and columns k = 0..n) begins:
1;
0, 1;
0, 0, 2;
0, 0, 0, 4;
0, 0, 0, 0, 8;
0, 0, 0, 0, 0, 16;
...
MATHEMATICA
Join[{1}, Flatten[Table[Join[{PadRight[{}, n], 2^(n-1)}], {n, 20}]]] (* Harvey P. Dale, Jan 04 2024 *)
PROG
(PARI) A134309(r, c)=if(r==c, 2^max(r-1, 0), 0) \\ M. F. Hasler, Mar 29 2022
CROSSREFS
Cf. A011782 (diagonal elements: 1 followed by 1, 2, 4, 8, ... = A000079: 2^n).
KEYWORD
nonn,tabl
AUTHOR
Gary W. Adamson, Oct 19 2007
STATUS
approved
A034494 a(n) = (7^n+1)/2. +10
12
1, 4, 25, 172, 1201, 8404, 58825, 411772, 2882401, 20176804, 141237625, 988663372, 6920643601, 48444505204, 339111536425, 2373780754972, 16616465284801, 116315256993604, 814206798955225, 5699447592686572 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Binomial transform of A081341. Inverse binomial transform of A081342. [R. J. Mathar, Oct 23 2008]
Number of compositions of even natural numbers into n parts <=6. [Adi Dani, May 28 2011]
From Charlie Marion, Jun 24 2011: (Start)
a(n)+(a(n)+1)+...+(a(n+1)-7^n-1)=(a(n+1)-7^n)+...+(a(n+1)-1). Let
S(2n) and S(2n+1) be the sets of addends on the left- and right-hand
sides, respectively, of the preceding equations. Then, since the
intersection of any 2 different S(i) is null and the union of all of
them is the positive integers, {S(i)} forms a partition of the
positive integers. See also A034659.
In general, for k>0, let b(n)=((4k+3)^n+1)/2. Then b(n)+(b(n)+1)+ ...
+(b(n+1)-(4k+3)^n-1)=k*((b(n+1)-(4k+3)^n)+ ... +(b(n+1)-1)). Then,
for each k, the set of addends on the two sides of these equations
also forms a partition of the positive integers. Also, with b(0)=1,
b(n)=(4k+3)*b(n-1)-(2k+1).
For k>0, let c(0)=1 and, for n>0, c(n)=(2*(2k+1))^n/2. Then the
sequence b(0),b(1),... is the binomial transform of the sequence
c(0),c(1),....
For k>0, let d(2n)=(2k+1)^(2n) and d(2n+1)=0. Then the sequence
b(0),b(1),... is the (2k+2)nd binomial transform of the sequence
d(0),d(1),.... (End)
LINKS
FORMULA
E.g.f.: exp(4*x)*cosh(3*x). - Paul Barry, Apr 20 2003
a(n) = 7a(n-1) - 3, a(0) = 1.
G.f.: (1-4*x)/((1-x)*(1-7*x)). - Philippe Deléham, Jul 11 2005
a(n) = 8*a(n-1)-7*a(n-2), a(0)=1, a(1)=4. [Philippe Deléham, Nov 15 2008]
a(n) = ((4+sqrt(9))^n+(4-sqrt(9))^n)/2. [Al Hakanson (hawkuu(AT)gmail.com), Dec 08 2008]
EXAMPLE
From Adi Dani, May 28 2011: (Start)
a(2)=25: there are 25 compositions of even numbers into 2 parts <=6:
(0,0)
(0,2),(2,0),(1,1)
(0,4),(4,0),(1,3),(3,1),(2,2)
(0,6),(6,0),(1,5),(5,1),(2,4),(4,2),(3,3)
(2,6),(6,2),(3,5),(5,3),(4,4)
(4,6),(6,4),(5,5)
(6,6)
(end)
MAPLE
A034494:=n->(7^n+1)/2: seq(A034494(n), n=0..30); # Wesley Ivan Hurt, Apr 09 2017
PROG
(Magma) [(7^n+1)/2: n in [0..30]]; // Vincenzo Librandi, Jun 16 2011
(PARI) a(n)=(7^n+1)/2 \\ Charles R Greathouse IV, Jul 02 2013
(PARI) Vec((1-4*x)/((1-x)*(1-7*x)) + O(x^100)) \\ Altug Alkan, Nov 01 2015
KEYWORD
nonn,easy
AUTHOR
STATUS
approved
A166469 Number of divisors of n which are not multiples of consecutive primes. +10
12
1, 2, 2, 3, 2, 3, 2, 4, 3, 4, 2, 4, 2, 4, 3, 5, 2, 4, 2, 6, 4, 4, 2, 5, 3, 4, 4, 6, 2, 5, 2, 6, 4, 4, 3, 5, 2, 4, 4, 8, 2, 6, 2, 6, 4, 4, 2, 6, 3, 6, 4, 6, 2, 5, 4, 8, 4, 4, 2, 7, 2, 4, 6, 7, 4, 6, 2, 6, 4, 6, 2, 6, 2, 4, 4, 6, 3, 6, 2, 10, 5, 4, 2, 8, 4, 4, 4, 8, 2, 6, 4, 6, 4, 4, 4, 7, 2, 6, 6, 9, 2, 6, 2, 8, 5 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,2
COMMENTS
Links various subsequences of A025487 with an unusual number of important sequences, including the Fibonacci, Lucas, and other generalized Fibonacci sequences (see cross-references).
If a number is a product of any number of consecutive primes, the number of its divisors which are not multiples of n consecutive primes is always a Fibonacci n-step number. See also A073485, A167447.
LINKS
Eric Weisstein's World of Mathematics, Fibonacci n-Step Number
FORMULA
a) If n has no prime gaps in its factorization (cf. A073491), then, if the canonical factorization of n into prime powers is the product of p_i^(e_i), a(n) is the sum of all products of one or more nonadjacent exponents, plus 1. For example, if A001221(n) = 3, a(n) = e_1*e_3 + e_1 + e_2 + e_3 + 1. If A001221(n) = k, the total number of terms always equals A000045(k+2).
The answer can also be computed in k steps, by finding the answers for the products of the first i powers, for i = 1 to i = k. Let the result of the i-th step be called r(i). r(1) = e_1 + 1; r(2) = e_1 + e_2 +1; for i > 2, r(i) = r(i-1) + e_i * r(i-2).
b) If n has prime gaps in its factorization, express it as a product of the minimum number of A073491's members possible. Then apply either of the above methods to each of those members, and multiply the results to get a(n). a(n) = A000005(n) iff n has no pair of consecutive primes as divisors.
a(n) = Sum_{d|n} (1-A296210(d)). - Antti Karttunen, Dec 15 2017
EXAMPLE
Since 3 of 30's 8 divisors (6, 15, and 30) are multiples of 2 or more consecutive primes, a(30) = 8 - 3 = 5.
MATHEMATICA
Array[DivisorSum[#, 1 &, FreeQ[Differences@ PrimePi@ FactorInteger[#][[All, 1]], 1] &] &, 105] (* Michael De Vlieger, Dec 16 2017 *)
PROG
(PARI)
A296210(n) = { if(1==n, return(0)); my(ps=factor(n)[, 1], pis=vector(length(ps), i, primepi(ps[i])), diffsminusones = vector(length(pis)-1, i, (pis[i+1]-pis[i])-1)); !factorback(diffsminusones); };
A166469(n) = sumdiv(n, d, !A296210(d)); \\ Antti Karttunen, Dec 15 2017
CROSSREFS
A(A002110(n)) = A000045(n+2); A(A097250(n)) = A000032(n+1). For more relationships involving Fibonacci and Lucas numbers, see A166470-A166473, comment on A081341.
A(A061742(n)) = A001045(n+2); A(A006939(n)) = A000085(n+1); A(A212170(n)) = A000142(n+1). A(A066120(n)) = A166474(n+1).
KEYWORD
nonn
AUTHOR
Matthew Vandermast, Nov 05 2009
EXTENSIONS
Edited by Matthew Vandermast, May 24 2012
STATUS
approved
A169604 a(n) = 3*6^n. +10
6
3, 18, 108, 648, 3888, 23328, 139968, 839808, 5038848, 30233088, 181398528, 1088391168, 6530347008, 39182082048, 235092492288, 1410554953728, 8463329722368, 50779978334208, 304679870005248, 1828079220031488 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
COMMENTS
a(n) = A081341(n+1).
Essentially first differences of A125682.
Binomial transform of A005053 without initial term 1.
Second binomial transform of A164346.
Inverse binomial transform of A169634.
Second inverse binomial transform of A103333 without initial term 1.
Contribution from Reinhard Zumkeller, May 02 2010: (Start)
a(n) = 3*A000400(n) = A000400(n+1)/2;
subsequence of A003586; a(n)=A003586(A014105(n)) for n<6. (End)
LINKS
FORMULA
a(n) = 6*a(n-1) for n > 0; a(0) = 3.
G.f.: 3/(1-6*x).
PROG
(Magma) [ 3*6^n: n in [0..19] ];
(PARI) a(n)=3*6^n \\ Charles R Greathouse IV, Oct 16 2015
CROSSREFS
Cf. A081341, A125682 ((6^n-1)*3/5), A005053 (expand (1-2x)/(1-5x)), A164346 (3*4^n), A169634 (3*7^n), A103333 (expand (1-5x)/(1-8x)).
KEYWORD
nonn,easy
AUTHOR
Klaus Brockhaus, Apr 04 2010
STATUS
approved
A081340 (5^n+(-1)^n)/2. +10
4
1, 2, 13, 62, 313, 1562, 7813, 39062, 195313, 976562, 4882813, 24414062, 122070313, 610351562, 3051757813, 15258789062, 76293945313, 381469726562, 1907348632813, 9536743164062, 47683715820313, 238418579101562 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
Binomial transform of A003665. 2nd binomial transform of (1,0,9,0,81,0,729,0,..). Case k=2 of family of recurrences a(n)=2k*a(n-1)-(k^2-9)*a(n-2), a(0)=0, a(1)=k. A003665 is case k=1.
LINKS
FORMULA
a(n) = 4*a(n-1) + 5*a(n-2), a(0)=1, a(1)=2.
G.f.: (1-2*x)/((1+x)*(1-5*x)).
E.g.f.: exp(2*x) * cosh(3*x).
a(n) = ((2+sqrt(9))^n+(2-sqrt(9))^n)/2. - Al Hakanson (hawkuu(AT)gmail.com), Dec 08 2008
a(n) = sum( k=0..n, A201730(n,k)*8^k ). - Philippe Deléham, Dec 06 2011
MATHEMATICA
CoefficientList[Series[(1 - 2 x) / ((1 + x) (1 - 5 x)), {x, 0, 20}], x] (* Vincenzo Librandi, Aug 08 2013 *)
PROG
(Sage) [lucas_number2(n, 4, -5)/2 for n in range(0, 22)] # Zerinvary Lajos, May 14 2009
(PARI) a(n)=(5^n+(-1)^n)/2 \\ Charles R Greathouse IV, Oct 07 2015
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Paul Barry, Mar 18 2003
STATUS
approved
A100852 Triangle read by rows: T(n,k) = 2^k * 3^n, 0 <= k <= n. +10
3
1, 3, 6, 9, 18, 36, 27, 54, 108, 216, 81, 162, 324, 648, 1296, 243, 486, 972, 1944, 3888, 7776, 729, 1458, 2916, 5832, 11664, 23328, 46656, 2187, 4374, 8748, 17496, 34992, 69984, 139968, 279936, 6561, 13122, 26244, 52488, 104976, 209952, 419904, 839808 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,2
COMMENTS
T(n,0) = A000244(n); T(n,n) = A000400(n) = A100851(n,n);
T(n,1) = A008776(n) for n>0;
T(n,2) = A003946(n+1) for n>1;
T(n,3) = A005051(n+1) for n>2;
T(n,n-1) = A081341(n+1) for n>0;
row sums give A016137.
LINKS
Michael De Vlieger, Table of n, a(n) for n = 0..10010 (Rows 0 <= n <= 140).
Eric Weisstein's World of Mathematics, Smooth Number
FORMULA
G.f.: 1/((1 - 3*x)(1 - 6*x*y)). - Ilya Gutkovskiy, Jun 03 2017
EXAMPLE
Triangle begins:
1;
3, 6;
9, 18, 36;
27, 54, 108, 216;
81, 162, 324, 648, 1296;
...
MATHEMATICA
Table[2^k*3^n, {n, 0, 140}, {k, 0, n}] // Flatten (* Michael De Vlieger, Mar 06 2017 *)
PROG
(PARI) for(n=0, 8, for(k=0, n, print1(2^k*3^n", "))) \\ Satish Bysany, Mar 06 2017
CROSSREFS
Cf. A100851, A003586, A065333(T(n, k))=1.
KEYWORD
nonn,tabl
AUTHOR
Reinhard Zumkeller, Nov 20 2004
STATUS
approved
A191347 Array read by antidiagonals: ((floor(sqrt(n)) + sqrt(n))^k + (floor(sqrt(n)) - sqrt(n))^k)/2 for columns k >= 0 and rows n >= 0. +10
3
1, 0, 1, 0, 1, 1, 0, 2, 1, 1, 0, 4, 3, 1, 1, 0, 8, 7, 4, 2, 1, 0, 16, 17, 10, 8, 2, 1, 0, 32, 41, 28, 32, 9, 2, 1, 0, 64, 99, 76, 128, 38, 10, 2, 1, 0, 128, 239, 208, 512, 161, 44, 11, 2, 1, 0, 256, 577, 568, 2048, 682, 196, 50, 12, 3, 1 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,8
LINKS
FORMULA
For each row n>=0 let T(n,0)=1 and T(n,1)=floor(sqrt(n)), then for each column k>=2: T(n,k)=T(n,k-2)*(n-T(n,1)^2) + T(n,k-1)*T(n,1)*2. - Charles L. Hohn, Aug 22 2019
T(n, k) = Sum_(i=0, floor((k+1)/2), binomial(k, 2*i)*floor(sqrtint(n))^(k-2*i)*n^i)) for n > 0, with T(0, 0) = 1 and T(0, k) = 0 for k > 0. - Michel Marcus, Aug 23 2019
EXAMPLE
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...
1, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, ...
1, 1, 3, 7, 17, 41, 99, 239, 577, 1393, 3363, ...
1, 1, 4, 10, 28, 76, 208, 568, 1552, 4240, 11584, ...
1, 2, 8, 32, 128, 512, 2048, 8192, 32768, 131072, 524288, ...
1, 2, 9, 38, 161, 682, 2889, 12238, 51841, 219602, 930249, ...
1, 2, 10, 44, 196, 872, 3880, 17264, 76816, 341792, 1520800, ...
1, 2, 11, 50, 233, 1082, 5027, 23354, 108497, 504050, 2341691, ...
1, 2, 12, 56, 272, 1312, 6336, 30592, 147712, 713216, 3443712, ...
1, 3, 18, 108, 648, 3888, 23328, 139968, 839808, 5038848, 30233088, ...
1, 3, 19, 117, 721, 4443, 27379, 168717, 1039681, 6406803, 39480499, ...
1, 3, 20, 126, 796, 5028, 31760, 200616, 1267216, 8004528, 50561600, ...
1, 3, 21, 135, 873, 5643, 36477, 235791, 1524177, 9852435, 63687141, ...
1, 3, 22, 144, 952, 6288, 41536, 274368, 1812352, 11971584, 79078912, ...
1, 3, 23, 153, 1033, 6963, 46943, 316473, 2133553, 14383683, 96969863, ...
...
PROG
(PARI) T(n, k) = if (n==0, k==0, my(x=sqrtint(n)); sum(i=0, (k+1)\2, binomial(k, 2*i)*x^(k-2*i)*n^i));
matrix(9, 9, n, k, T(n-1, k-1)) \\ Michel Marcus, Aug 22 2019
(PARI) T(n, k) = if (k==0, 1, if (k==1, sqrtint(n), T(n, k-2)*(n-T(n, 1)^2) + T(n, k-1)*T(n, 1)*2));
matrix(9, 9, n, k, T(n-1, k-1)) \\ Charles L. Hohn, Aug 22 2019
CROSSREFS
Row 1 is A000007, row 2 is A011782, row 3 is A001333, row 4 is A026150, row 5 is A081294, row 6 is A001077, row 7 is A084059, row 8 is A108851, row 9 is A084128, row 10 is A081341, row 11 is A005667, row 13 is A141041.
Row 3*2 is A002203, row 4*2 is A080040, row 5*2 is A155543, row 6*2 is A014448, row 8*2 is A080042, row 9*2 is A170931, row 11*2 is A085447.
Cf. A191348 which uses ceiling() in place of floor().
KEYWORD
nonn,tabl
AUTHOR
Charles L. Hohn, May 31 2011
STATUS
approved
A191348 Array read by antidiagonals: ((ceiling(sqrt(n)) + sqrt(n))^k + (ceiling(sqrt(n)) - sqrt(n))^k)/2 for columns k >= 0 and rows n >= 0. +10
3
1, 0, 1, 0, 1, 1, 0, 2, 2, 1, 0, 4, 6, 2, 1, 0, 8, 20, 7, 2, 1, 0, 16, 68, 26, 8, 3, 1, 0, 32, 232, 97, 32, 14, 3, 1, 0, 64, 792, 362, 128, 72, 15, 3, 1, 0, 128, 2704, 1351, 512, 376, 81, 16, 3, 1, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,8
LINKS
FORMULA
For each row n >= 0 let T(n,0)=1 and T(n,1) = ceiling(sqrt(n)), then for each column k >= 2: T(n,k) = T(n,k-2)*(n-T(n,1)^2) + T(n,k-1)*T(n,1)*2. - Charles L. Hohn, Aug 23 2019
EXAMPLE
1, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, ...
1, 1, 2, 4, 8, 16, 32, 64, 128, 256, 512, ...
1, 2, 6, 20, 68, 232, 792, 2704, 9232, 31520, 107616, ...
1, 2, 7, 26, 97, 362, 1351, 5042, 18817, 70226, 262087, ...
1, 2, 8, 32, 128, 512, 2048, 8192, 32768, 131072, 524288, ...
1, 3, 14, 72, 376, 1968, 10304, 53952, 282496, 1479168, 7745024, ...
1, 3, 15, 81, 441, 2403, 13095, 71361, 388881, 2119203, 11548575, ...
1, 3, 16, 90, 508, 2868, 16192, 91416, 516112, 2913840, 16450816, ...
1, 3, 17, 99, 577, 3363, 19601, 114243, 665857, 3880899, 22619537, ...
1, 3, 18, 108, 648, 3888, 23328, 139968, 839808, 5038848, 30233088, ...
1, 4, 26, 184, 1316, 9424, 67496, 483424, 3462416, 24798784, 177615776, ...
1, 4, 27, 196, 1433, 10484, 76707, 561236, 4106353, 30044644, 219825387, ...
1, 4, 28, 208, 1552, 11584, 86464, 645376, 4817152, 35955712, 268377088, ...
1, 4, 29, 220, 1673, 12724, 96773, 736012, 5597777, 42574180, 323800109, ...
1, 4, 30, 232, 1796, 13904, 107640, 833312, 6451216, 49943104, 386642400, ...
...
PROG
(PARI) T(n, k) = if (k==0, 1, if (k==1, ceil(sqrt(n)), T(n, k-2)*(n-T(n, 1)^2) + T(n, k-1)*T(n, 1)*2));
matrix(9, 9, n, k, T(n-1, k-1)) \\ Charles L. Hohn, Aug 23 2019
CROSSREFS
Row 1 is A000007, row 2 is A011782, row 3 is A006012, row 4 is A001075, row 5 is A081294, row 6 is A098648, row 7 is A084120, row 8 is A146963, row 9 is A001541, row 10 is A081341, row 11 is A084134, row 13 is A090965.
Row 3*2 is A056236, row 4*2 is A003500, row 5*2 is A155543, row 9*2 is A003499.
Cf. A191347 which uses floor() in place of ceiling().
KEYWORD
nonn,tabl
AUTHOR
Charles L. Hohn, May 31 2011
STATUS
approved
A192396 Square array T(n, k) = floor(((k+1)^n - (1+(-1)^k)/2)/2) read by antidiagonals. +10
2
0, 0, 0, 0, 1, 0, 0, 2, 1, 0, 0, 4, 4, 2, 0, 0, 8, 13, 8, 2, 0, 0, 16, 40, 32, 12, 3, 0, 0, 32, 121, 128, 62, 18, 3, 0, 0, 64, 364, 512, 312, 108, 24, 4, 0, 0, 128, 1093, 2048, 1562, 648, 171, 32, 4, 0, 0, 256, 3280, 8192, 7812, 3888, 1200, 256, 40, 5, 0 (list; table; graph; refs; listen; history; text; internal format)
OFFSET
0,8
COMMENTS
T(n,k) is the number of compositions of odd natural numbers into n parts <=k.
LINKS
EXAMPLE
T(2,4)=12: there are 12 compositions of odd natural numbers into 2 parts <=4
1: (0,1), (1,0);
3: (1,2), (2,1), (0,3), (3,0);
5: (1,4), (4,1), (2,3), (3,2);
7: (3,4), (4,3).
The table starts
0, 0, 0, 0, 0, 0, ... A000004;
0, 1, 1, 2, 2, 3, ... A004526;
0, 2, 4, 8, 12, 18, ... A007590;
0, 4, 13, 32, 62, 108, ... A036487;
0, 8, 40, 128, 312, 648, ... A191903;
0, 16, 121, 512, 1562, 3888, ... A191902;
. . . . ...
with columns: A000004, A000079, A003462, A004171, A128531, A081341, ... .
Antidiagonal triangle begins:
0;
0, 0;
0, 1, 0;
0, 2, 1, 0;
0, 4, 4, 2, 0;
0, 8, 13, 8, 2, 0;
0, 16, 40, 32, 12, 3, 0;
0, 32, 121, 128, 62, 18, 3, 0;
0, 64, 364, 512, 312, 108, 24, 4, 0;
MAPLE
A192396 := proc(n, k) (k+1)^n-(1+(-1)^k)/2 ; floor(%/2) ; end proc:
seq(seq( A192396(d-k, k), k=0..d), d=0..10) ; # R. J. Mathar, Jun 30 2011
MATHEMATICA
T[n_, k_]:= Floor[((k+1)^n - (1+(-1)^k)/2)/2];
Table[T[n-k, k], {n, 0, 12}, {k, 0, n}]//Flatten
PROG
(Magma)
A192396:= func< n, k | Floor(((k+1)^n - (1+(-1)^k)/2)/2) >;
[A192396(n-k, k): k in [0..n], n in [0..12]]; // G. C. Greubel, Jul 11 2023
(SageMath)
def A192396(n, k): return ((k+1)^n - ((k+1)%2))//2
flatten([[A192396(n-k, k) for k in range(n+1)] for n in range(13)]) # G. C. Greubel, Jul 11 2023
CROSSREFS
KEYWORD
nonn,tabl,easy
AUTHOR
Adi Dani, Jun 29 2011
STATUS
approved
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Last modified August 30 15:38 EDT 2024. Contains 375545 sequences. (Running on oeis4.)