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Search: a104842 -id:a104842
Displaying 1-10 of 20 results found. page 1 2
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A104824 Primes from merging of 4 successive digits in decimal expansion of Pi. +10
31
4159, 5897, 9323, 8419, 1693, 8209, 9749, 5923, 2089, 2803, 4211, 7253, 8111, 1117, 7019, 193, 8521, 6229, 1097, 6659, 8233, 7867, 1201, 9091, 5669, 4603, 4861, 3607, 4127, 631, 5881, 5209, 9209, 4091, 3643, 5903, 11, 113, 6521, 1511, 1609, 9433 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Leading zeros permitted. - Harvey P. Dale, Dec 09 2013
LINKS
MATHEMATICA
With[{pi = FromDigits/@Partition[RealDigits[Pi, 10, 500][[1]], 4, 1]}, Select[pi, PrimeQ]] (* Vincenzo Librandi, Apr 21 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 27 2005
STATUS
approved
A104826 Primes from merging of 6 successive digits in decimal expansion of Pi. +10
31
314159, 358979, 589793, 462643, 971693, 169399, 592307, 348253, 534211, 808651, 844609, 822317, 725359, 502841, 102701, 288109, 612847, 337867, 104543, 815209, 925409, 917153, 665213, 951941 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Leading zeros are not permitted, so each term is 6 digits in length. - Harvey P. Dale, Oct 23 2011
LINKS
MATHEMATICA
With[{len=6}, FromDigits/@Select[Partition[RealDigits[Pi, 10, 1000][[1]], len, 1], PrimeQ[FromDigits[#]]&&IntegerLength[FromDigits[#]]==len&]] (* Harvey P. Dale, Oct 23 2011 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 27 2005
STATUS
approved
A104825 Primes from merging of 5 successive digits in decimal expansion of Pi. +10
24
14159, 35897, 58979, 38327, 97169, 71693, 39937, 9749, 30781, 20899, 34211, 64709, 47093, 82231, 84811, 46229, 81097, 56659, 66593, 86783, 85669, 66923, 34603, 93607, 60631, 9209, 25409, 54091, 25903, 113, 33053, 65213, 13841, 51941, 94151 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Because leading zeros are permitted, some terms have fewer than 5 digits. - Harvey P. Dale, Mar 01 2023
LINKS
MATHEMATICA
With[{pi=FromDigits/@Partition[RealDigits[Pi, 10, 2000][[1]], 5, 1]}, Select[pi, PrimeQ]] (* Harvey P. Dale, Oct 18 2011 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 27 2005
STATUS
approved
A104841 The first n-digit prime occurring in the decimal expansion of Pi, A000796. +10
7
3, 31, 653, 4159, 14159, 314159, 1592653, 28841971, 795028841, 5926535897, 93238462643, 141592653589, 9265358979323, 23846264338327, 841971693993751, 8628034825342117, 89793238462643383, 348253421170679821, 3832795028841971693, 89793238462643383279 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
For the next n-digit primes, see the b-file (link).
Sequence A198344 gives the position of these primes withing the digits of Pi.
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..1000 (terms 1..162 from M. F. Hasler)
PROG
(PARI) default(realprecision, 2000); A104841(n)={for( c=0, default(realprecision)-n-2, Pi\.1^c%10 & ispseudoprime(p=Pi\.1^(n+c-1)%10^n) & return(p)); error("Please increase default(realprecision) to calculate A104841("n").")} \\ M. F. Hasler, Oct 23 2011
(Python)
from sympy import S, isprime
pi = "3"+str(S.Pi.n(10**5))[2:] # or load data from file
def A104841_A198344(n): return next(((p, i+1) for i in range(len(pi)-n) if pi[i]!="0" and isprime(p:=int(pi[i:i+n]))), "not enough digits")
print([A104841_A198344(n)[0] for n in range(1, 21)]) # Michael S. Branicky, Dec 28 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 27 2005
STATUS
approved
A198344 Position of the first n-digit prime occurring in the decimal expansion of Pi, A000796. +10
4
1, 1, 8, 3, 2, 1, 4, 34, 30, 5, 15, 2, 6, 17, 36, 82, 12, 87, 26, 12, 25, 215, 35, 18, 17, 3, 41, 17, 234, 17, 167, 92, 251, 15, 9, 12, 31, 1, 57, 290, 4, 99, 218, 502, 48, 164, 198, 201, 128, 7, 363, 143, 11, 138, 487, 32, 230, 82, 355, 515, 334, 186, 176, 223 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,3
COMMENTS
Differs from A104842 in a(22), a(43), a(55),..., because here, leading zeros are not allowed.
The corresponding primes are listed in A104841.
Among the first 99 terms, even though values up to 825 occur, the values 1 and 17 occur 4 times, 12 and 57 occur 3 times, and numbers as large as 82, 164, 167 and 234 occur twice.
LINKS
Michael S. Branicky, Table of n, a(n) for n = 1..1000 (terms 1..162 from M. F. Hasler)
EXAMPLE
a(1)=1 because the initial digit "3" of Pi is prime.
a(2)=a(6)=a(38)=1 because the first 2, 6, and 38 digits of Pi (including the initial 3) also form the primes 31, 314159 and 31415926535897932384626433832795028841, cf. A005042 and A060421.
MATHEMATICA
With[{pd=RealDigits[Pi, 10, 1000][[1]]}, Table[Position[Partition[pd, n, 1], _?(PrimeQ[FromDigits[#]]&&#[[1]]!=0&), {1}, 1, Heads->False], {n, 60}]]// Flatten (* Harvey P. Dale, Apr 25 2016 *)
PROG
(PARI) A198344(n)=for(c=0, 9e9, ispseudoprime(Pi\.1^(n+c-1)%10^n)&Pi\.1^c%10&return(c+1)) /* Replace upper limit 9e9 by "default(realprecision)-n" to avoid an error message and return 0 in case no n-digit prime is found */
(Python) # uses code in A104841
print([A104841_A198344(n)[1] for n in range(1, 65)]) # Michael S. Branicky, Dec 28 2022
CROSSREFS
KEYWORD
nonn,base
AUTHOR
M. F. Hasler, Oct 23 2011
STATUS
approved
A104830 Primes from merging of 10 successive digits in decimal expansion of Pi. +10
3
5926535897, 4197169399, 1693993751, 7510582097, 348253421, 4825342117, 5822317253, 812848111, 2841027019, 8521105559, 8954930381, 4756482337, 2712019091, 5432664821, 3266482133, 6072602491, 5588174881, 8815209209 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Leading zeros are permitted, so some terms are less than 10 digits in length. - Bruno Berselli, May 01 2013
LINKS
MATHEMATICA
With[{pi = FromDigits/@Partition[RealDigits[Pi, 10, 500][[1]], 10, 1]}, Select[pi, PrimeQ]] (* Vincenzo Librandi, Apr 21 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 27 2005
STATUS
approved
A104823 Primes from merging of three successive digits in decimal expansion of Pi. +10
1
653, 643, 433, 383, 419, 197, 971, 937, 751, 97, 307, 89, 421, 211, 67, 821, 823, 647, 709, 223, 317, 359, 811, 701, 19, 193, 521, 211, 229, 881, 109, 97, 659, 593, 461, 823, 233, 337, 271, 19, 821, 607, 491, 127 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Leading zeros are permitted, so not every term is 3 digits in length. - Harvey P. Dale, Oct 24 2011
LINKS
MATHEMATICA
With[{pi = FromDigits/@Partition[RealDigits[Pi, 10, 500][[1]], 3, 1]}, Select[pi, PrimeQ]] (* Vincenzo Librandi, Apr 23 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 27 2005
STATUS
approved
A104827 Primes from merging of 7 successive digits in decimal expansion of Pi. +10
1
1592653, 6535897, 2643383, 5028841, 6939937, 3993751, 348253, 1170679, 8086513, 5822317, 1725359, 4930381, 2881097, 4612847, 3165271, 2712019, 1201909, 4914127, 917153, 1133053, 3841469, 1469519, 6951941, 9433057 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
COMMENTS
Leading zeros are permitted so some terms may have fewer than 7 digits. For example, 223, 907, 3137, and 4229 are all terms. - Harvey P. Dale, May 24 2020
LINKS
MATHEMATICA
With[{pi = FromDigits/@Partition[RealDigits[Pi, 10, 500][[1]], 7, 1]}, Select[pi, PrimeQ]] (* Vincenzo Librandi, Apr 21 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 27 2005
STATUS
approved
A104828 Primes from merging of 8 successive digits in decimal expansion of Pi. +10
1
28841971, 41971693, 82534211, 42117067, 30664709, 5822317, 31725359, 49303819, 75648233, 37867831, 71201909, 48566923, 26648213, 13393607, 25409171, 1133053, 9433057 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
MATHEMATICA
With[{pi = FromDigits/@Partition[RealDigits[Pi, 10, 500][[1]], 8, 1]}, Select[pi, PrimeQ]] (* Vincenzo Librandi, Apr 21 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 27 2005
STATUS
approved
A104829 Primes from merging of 9 successive digits in decimal expansion of Pi. +10
1
795028841, 502884197, 28841971, 884197169, 971693993, 348253421, 421170679, 306647093, 812848111, 659334461, 233786783, 648566923, 346034861, 326648213, 829254091, 678925903, 1133053, 959195309, 530921861, 938183011 (list; graph; refs; listen; history; text; internal format)
OFFSET
1,1
LINKS
MATHEMATICA
With[{pi = FromDigits/@Partition[RealDigits[Pi, 10, 500][[1]], 9, 1]}, Select[pi, PrimeQ]] (* Vincenzo Librandi, Apr 21 2013 *)
CROSSREFS
KEYWORD
nonn,base
AUTHOR
Zak Seidov, Mar 27 2005
STATUS
approved
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Last modified August 29 06:09 EDT 2024. Contains 375510 sequences. (Running on oeis4.)