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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A180061 Numbers k such that (2^(2^k mod k) mod k) = 4.

Original entry on oeis.org

5, 6, 7, 9, 11, 12, 13, 17, 19, 21, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 63, 67, 71, 73, 79, 83, 89, 97, 101, 103, 107, 109, 113, 121, 127, 131, 133, 137, 139, 149, 151, 157, 163, 167, 172, 173, 179, 181, 190, 191, 193, 196, 197, 199, 211
Offset: 1

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Author

Juri-Stepan Gerasimov, Jan 14 2011

Keywords

Comments

The composite terms in this sequence start 6, 9, 12, 21, 63, 121, 133, 172, 190, 196, ... - R. J. Mathar, Jan 14 2011

Crossrefs

Programs

  • Mathematica
    Select[Range[300],PowerMod[2,PowerMod[2,#,#],#]==4&] (* Harvey P. Dale, Sep 08 2016 *)
  • PARI
    s=[]; for(n=1, 1000, if((2^(2^n%n)%n)==4, s=concat(s, n))); s \\ Colin Barker, Jun 27 2014

Formula

A180060(a(n)) = 4.

Extensions

Terms corrected by R. J. Mathar, Jan 14 2011
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