cp's OEIS Frontend

This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.

Showing 1-2 of 2 results.

A065831 Primes found in A065830.

Original entry on oeis.org

3, 13, 881, 14436001, 461952047, 14782465513, 7568622343067, 3968137871002260679, 65013970878501038966321
Offset: 1

Views

Author

Patrick De Geest, Nov 24 2001

Keywords

Crossrefs

Formula

a(n) = A065830(A065832(n)). - Jinyuan Wang, Aug 31 2021

A065570 Numbers k such that the first k ternary digits found in the decimal expansion of Pi form a prime.

Original entry on oeis.org

264, 274, 322, 751, 3112, 24842, 32731
Offset: 1

Views

Author

Robert G. Wilson v, Nov 30 2001

Keywords

Crossrefs

Cf. A065832.

Programs

  • Mathematica
    p = First[ RealDigits[ Pi, 10, 10^5]]; p = p[[ Select[ Range[10^5], p[[ # ]] == 0 || p[[ # ]] == 1 || p[[ # ]] == 2 & ]]]; Do[ If[ PrimeQ[ FromDigits[ Take[p, n], 3]], Print[n]], {n, 1, 4000} ]
    Module[{nn=30000,pd},pd=Select[RealDigits[Pi,10,nn][[1]],#<3&];Select[ Range[ Length[pd]],PrimeQ[FromDigits[Take[pd,#],3]]&]] (* The program generates the first five terms of the sequence. To generate more, increase the constant for "nn," but it will take a long time to run and the value of nn may be to be 150,000 or more. *) (* Harvey P. Dale, Jul 31 2020 *)

Extensions

a(6)-a(7) from Chai Wah Wu, Apr 07 2020
Showing 1-2 of 2 results.