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%I #22 Feb 23 2017 22:56:01
%S 1,13,19,29,37,45,51,61,63,65,69,117,171,181,199,201,217,221,265,337,
%T 627,631,881,1035,1507,1525,1627,1641,2037,3175,4639,6445,21537,29801,
%U 30521,30917,37877,49725,50877,57537,61337,118141,125169,200961,204117,283445,395125,829489
%N Numbers k such that 32771*2^k + 1 is prime.
%C a(48) = 829489, 1438879 is such that 32771*2^1438879 + 1 is prime with 433151 digits, 829489 < a(49) <= 1438879.
%t Select[Range@ 3000, PrimeQ[32771*2^# + 1] &] (* _Michael De Vlieger_, Jan 23 2017 *)
%o (PFGW) 32771*2^$a+1
%o $a: from 1 to 1000001 step 2
%o (PARI) list(limit)=my(i=1); while(i<limit, if(isprime(32771*2^i+1),print1(i, ", ")); i++) \\ _Anders Hellström_, Feb 04 2017
%Y Cf. A002253.
%K nonn
%O 1,2
%A _Pierre CAMI_, Jan 22 2017
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