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Search: a164539 -id:a164539
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a(n) = 8*a(n-2) for n > 2; a(1) = 1, a(2) = 12.
+10
6
1, 12, 8, 96, 64, 768, 512, 6144, 4096, 49152, 32768, 393216, 262144, 3145728, 2097152, 25165824, 16777216, 201326592, 134217728, 1610612736, 1073741824, 12884901888, 8589934592, 103079215104, 68719476736, 824633720832
OFFSET
1,2
COMMENTS
Interleaving of A001018 and 12*A001018.
Binomial transform is A164539.
FORMULA
a(n) = (5+(-1)^n)*2^(1/4*(6*n-11+3*(-1)^n)).
G.f.: x*(1+12*x)/(1-8*x^2).
MATHEMATICA
Riffle[#, 12*#] & [8^Range[0, 14]] (* or *)
LinearRecurrence[{0, 8}, {1, 12}, 30] (* Paolo Xausa, Apr 22 2024 *)
PROG
(Magma) [ n le 2 select 11*n-10 else 8*Self(n-2): n in [1..26] ];
CROSSREFS
Cf. A001018 (powers of 8), A164539.
KEYWORD
nonn,easy
AUTHOR
Klaus Brockhaus, Aug 20 2009
STATUS
approved
a(n) = 4*a(n-1) + 4*a(n-2) for n > 1; a(0) = 1, a(1) = 14.
+10
3
1, 14, 60, 296, 1424, 6880, 33216, 160384, 774400, 3739136, 18054144, 87173120, 420909056, 2032328704, 9812951040, 47381118976, 228776280064, 1104629596160, 5333623504896, 25753012404224, 124346543636480, 600398224162816
OFFSET
0,2
COMMENTS
Binomial transform of A164539. Second binomial transform of A164675. Inverse binomial transform of A164541.
LINKS
Martin Burtscher, Igor Szczyrba, RafaƂ Szczyrba, Analytic Representations of the n-anacci Constants and Generalizations Thereof, Journal of Integer Sequences, Vol. 18 (2015), Article 15.4.5.
FORMULA
a(n) = 4*a(n-1) + 4*a(n-2) for n > 1; a(0) = 1, a(1) = 14.
G.f.: (1+10*x)/(1-4*x-4*x^2).
a(n) = ((1+3*sqrt(2))*(2+2*sqrt(2))^n + (1-3*sqrt(2))*(2-2*sqrt(2))^n)/2.
MATHEMATICA
LinearRecurrence[{4, 4}, {1, 14}, 30] (* Harvey P. Dale, Jul 18 2024 *)
PROG
(Magma) Z<x>:=PolynomialRing(Integers()); N<r>:=NumberField(x^2-2); S:=[ ((1+3*r)*(2+2*r)^n+(1-3*r)*(2-2*r)^n)/2: n in [0..21] ]; [ Integers()!S[j]: j in [1..#S] ]; // Klaus Brockhaus, Aug 20 2009
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Al Hakanson (hawkuu(AT)gmail.com), Aug 15 2009
EXTENSIONS
Edited and extended beyond a(5) by Klaus Brockhaus, Aug 20 2009
STATUS
approved

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