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Primes in A112714.
2

%I #9 May 23 2017 21:59:23

%S 3,7,11,23,31,47,79,127,191,223,239,383,479,607,863,991,1087,1151,

%T 1279,1471,1663,2111,2239,2687,2879,3391,3583,3967,5119,5503,6143,

%U 6271,6911,7039,8191,8447,8831,9343,10111,11519,11903,12671,12799,13183,13567

%N Primes in A112714.

%H Robert Israel, <a href="/A112715/b112715.txt">Table of n, a(n) for n = 1..10000</a>

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

%p N:= 10^6: # to get all terms <= N

%p 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

%t 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 *)

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

%Y Cf. A080076.

%K easy,nonn

%O 1,1

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