A319505 Numbers k such that 2^(k*(k+1)/2) == -1 (mod k^2).

1, 389993, 476729, 2927297, 3048569, 3862529, 3914049, 4755729, 5077209, 7460409, 9009489, 9314009, 11066649, 11981409, 12928289, 13342769, 15371609, 15574449, 22975249, 34429449, 44876649, 57046209, 66358417, 66963369, 79552209, 83006769, 96783929, 99127313, 118462737, 126209609, 128566689, 139745969

Offset

1,2

Links

Table of n, a(n) for n=1..32.

Prog

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

Crossrefs

Cf. A006125, A077816, A126884.

Sequence in context: A258686 A157739 A233491 * A106778 A164987 A176765

Adjacent sequences: A319502 A319503 A319504 * A319506 A319507 A319508

Keyword

nonn

Author

Altug Alkan, Sep 21 2018

Status

approved