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A112715 Primes in A112714. 2
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 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 17 18:58 EDT 2019. Contains 328127 sequences. (Running on oeis4.)