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.

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A319216 Numbers k such that k^2 + 1 divides 2^k + 2.

Original entry on oeis.org

0, 1, 3, 15, 79, 511, 4095, 6735, 65535, 2097151, 16777215, 75955411, 68719476735, 137438953471
Offset: 1

Views

Author

Altug Alkan, Sep 13 2018, following a suggestion from Max Alekseyev

Keywords

Comments

Numbers t such that 2^t-1 is a term are 0, 1, 2, 4, 9, 12, 16, 21, ...
Primes p such that 2^((p^2-1)/2)-1 is a term are 3, 5, 7, 13, 19, 29, 37, 43, 47, 61, 71, 89, 103, 107, 127, 131, 139, 173, 191, 211, ...(cf. A062326).
a(14) > 10^11. - Hiroaki Yamanouchi, Sep 14 2018

Crossrefs

Cf. A015921, A062326, A097958, A244673, A247220.

Programs

  • PARI
    isok(n)=Mod(2, n^2+1)^n==-2;

Extensions

a(13) from Hiroaki Yamanouchi, Sep 14 2018
a(14) from Giovanni Resta, Sep 17 2018
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Started in 1964 by Neil J. A. Sloane | Maintained by The OEIS Foundation Inc.

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