A112715 Primes in A112714.

3, 7, 11, 23, 31, 47, 79, 127, 191, 223, 239, 383, 479, 607, 863, 991, 1087, 1151, 1279, 1471, 1663, 2111, 2239, 2687, 2879, 3391, 3583, 3967, 5119, 5503, 6143, 6271, 6911, 7039, 8191, 8447, 8831, 9343, 10111, 11519, 11903, 12671, 12799, 13183, 13567

Offset

1,1

Links

Robert Israel, Table of n, a(n) for n = 1..10000

Example

a(1)=3 because 3=1*2^2-1 and it is the first prime of this form.

Maple

N:= 10^6: # to get all terms <= N
sort(convert(select(isprime, {seq(seq(k*2^m-1, k=1..min((N+1)/2^m, 2^m-1), 2), m=1..ilog2(N+1))}), list)); # Robert Israel, May 23 2017

Mathematica

Take[Sort@ Select[Flatten@ Table[k 2^m - 1, {m, 0, 15}, {k, 1, 2^m - 1, 2}], PrimeQ], 45] (* Michael De Vlieger, May 23 2017, after Robert G. Wilson v at A112714 *)

Prog

(PARI) for(n=2, 8, for(k=2^(n-2)+1, 2^n, M=k*2^n-1; if(isprime(M), print1(M", "), 0)))

Crossrefs

Cf. A080076.

Sequence in context: A287459 A095102 A192614 * A106935 A308576 A116362

Adjacent sequences: A112712 A112713 A112714 * A112716 A112717 A112718

Keyword

easy,nonn

Author

Jose Brox (tautocrona(AT)terra.es), Dec 31 2005

Status

approved