A179003 Numbers k such that 2^(2*k-1) mod (2*k+1) is prime.

1, 2, 4, 6, 7, 10, 16, 18, 19, 25, 28, 30, 31, 34, 36, 37, 38, 43, 46, 49, 52, 55, 58, 61, 64, 67, 70, 78, 79, 87, 88, 91, 96, 97, 100, 106, 107, 109, 112, 115, 118, 124, 126, 133, 138, 145, 147, 148, 151, 154, 156, 157, 160, 163, 169, 180

Offset: 1

Author

Juri-Stepan Gerasimov, Jan 03 2011

Keywords

• nonn

Crossrefs

Cf. A000040, A178537, A178970.

Programs

Mathematica

fQ[n_] := PrimeQ@ PowerMod[2, 2 n - 1, 2 n + 1]; Select[ Range@ 180, fQ]