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 1-1 of 1 results.

A265630 Numbers n > 1 such that 2^m == 1 (mod n^2), where m = A002326((n-1)/2).

Original entry on oeis.org

1093, 3511, 7651, 10533, 14209, 17555, 22953, 31599, 42627, 45643, 52665, 99463, 136929, 157995, 228215, 298389, 410787, 684645, 2053935, 3837523, 11512569, 19187615, 26862661, 34537707, 49887799, 57562845, 80587983, 134313305, 149663397, 172688535, 241763949, 249438995, 349214593, 402939915, 448990191, 748316985, 1047643779, 1208819745, 1746072965, 2244950955, 3142931337, 5238218895, 15714656685
Offset: 1

Views

Author

Thomas Ordowski, Dec 11 2015

Keywords

Comments

A subsequence of A077816.
Odd numbers n > 1 such that A237292((n-1)/2) = 1.
Indices k such that A077816(k) is not in this sequence are 2, 13, 14, 16, 22, 24, 25, 27, 28, 30, ... - Altug Alkan, Dec 11 2015
There are no other terms, unless there are other Wieferich primes (A001220) besides 1093 and 3511. - Max Alekseyev, Dec 11 2015

Crossrefs

Programs

  • Mathematica
    Select[Range[10^6], Mod[2^MultiplicativeOrder[2, 2 ((# - 1)/2) + 1], #^2] == 1 &] (* Michael De Vlieger, Dec 11 2015 *)
  • PARI
    a002326(n) = znorder(Mod(2, 2*n+1));
    a237292(n) = a002326(2*n*(n+1))/a002326(n);
    for(n=1, 1e8, if(a237292(n)==1, print1(2*n+1, ", "))) \\ Altug Alkan, Dec 11 2015

Extensions

More terms from Altug Alkan, Dec 11 2015
Missing terms a(28)-a(30) and further terms a(34)-a(43) added by Max Alekseyev, Dec 11 2015
Showing 1-1 of 1 results.