A179002 Primes p such that 2^(2p-1) mod (2p+1) is prime.

2, 7, 19, 31, 37, 43, 61, 67, 79, 97, 107, 109, 151, 157, 163, 199, 223, 241, 257, 269, 271, 307, 337, 349, 379, 409, 421, 433, 439, 523, 557, 577, 601, 613, 619, 631, 673, 691, 739, 757, 787, 811, 823, 853, 863, 877, 883, 919, 967, 991, 1009, 1051, 1061, 1063, 1117, 1153, 1181, 1213

Offset: 1

Author

Juri-Stepan Gerasimov, Jan 03 2011

Keywords

• nonn

Crossrefs

Cf. A000040, A178537, A178970.

Programs

Mathematica

 fQ[n_] := PrimeQ@ PowerMod[2, 2n - 1, 2n + 1]; Select[ Prime@ Range@ 200, fQ]

Formula

A178970(a(n)=A000040(i))=A000040(k).