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.

A247831 Pseudoprimes to base 2 divisible by 3511^2, including the even pseudoprimes.

Original entry on oeis.org

12327121, 129816911251, 259621495381, 346157884801, 605767053061, 6317168754781, 6922923480721, 12634325182441, 18518799663001, 21634109682121, 24273469559431, 57114029344321, 65681131896901, 102718706568661, 135083316211741, 135818875521811, 153342494379361
Offset: 1

Views

Author

Felix Fröhlich, Sep 24 2014

Keywords

Comments

Numbers k such that 2^k == 2 (mod k) and k is divisible by 3511^2.
Unless there are other Wieferich primes (A001220) besides 1093 and 3511, the intersection and the union of this sequence with A247830 are given by A219346 and A158358, respectively, and the even terms are given by A295740. - Max Alekseyev, Nov 26 2017 [The indices of the even terms in this sequence are 430, 525, 543, 701, 811, 826, 937, 1235, 1277, 1388, ... - Jianing Song, Feb 08 2019]

Crossrefs

Subsequence of each of (A001567 U A006935), A015919, A158358 composed of the terms divisible by 3511^2.

Programs

  • PARI
    vi=readvec("b158358.txt")
    for(n=1, #vi, if(Mod(vi[n], 3511^2)==0, print1(vi[n], ", ")))
    
  • PARI
    list(N)=select(k->Mod(2, k)^k==2, 3511^2*vector(N\3511^2\2, i, i)) \\ Jianing Song, Feb 07 2019

Extensions

Name changed by Jianing Song, Feb 07 2019 to include the even pseudoprimes to base 2 (A006935) at the suggestion of Max Alekseyev.