A215434 Primes of form 2^k + k^2 - 1.

2, 7, 31, 1123, 1180591620717411308323, 21778071482940061661655974875633165551139, 89202980794122492566142873090593446023942979, 1569275433846670190958947355801916604025588861116008664323

Offset

1,1

Links

Vincenzo Librandi, Table of n, a(n) for n = 1..11

Mathematica

Select[Table[2^n + n^2 - 1, {n, 0, 300}], PrimeQ]

Prog

(Magma) [a: n in [0..250] | IsPrime(a) where a is 2^n+n^2-1];

Crossrefs

Cf. A035325, A061119, A215439.

Sequence in context: A147782 A102165 A102160 * A355541 A158940 A102161

Adjacent sequences: A215431 A215432 A215433 * A215435 A215436 A215437

Keyword

nonn,easy

Author

Vincenzo Librandi, Sep 03 2012

Status

approved