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Numbers b such that b^(2^n) + 2 is prime for n from 0 to 4.
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%I #8 May 09 2013 22:43:54

%S 22155,1864149,2760681,6222765,22687797,25631319,29309589,33333069,

%T 36490905,56310891,60212889,74097849,76008207,80864685,84214395,

%U 132006225,132621171,137362521,138993381,152223885,154185525,175950081,188261481,188677335,194279955

%N Numbers b such that b^(2^n) + 2 is prime for n from 0 to 4.

%C Generalized Fermat numbers of the form b^(2^n) + k with k = 2 here.

%C For b = 2760681, b^(2^n) + 2 is prime for n from 0 to 5

%o (PARI) k=2;forstep(b=1,5*10^7,[4,2,2,2],i=0;for(n=0,4,m=b^2^n+k;if(isprime(m),i++;if(i>4,print([b,m,n,i])))))

%Y Cf. A070694, A225321

%K nonn

%O 1,1

%A _Robin Garcia_, May 06 2013

%E a(10)-a(25) from _Giovanni Resta_, May 06 2013