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%I #6 May 06 2013 00:48:18
%S 2564954,4505138,6319754,10004666,13410068,28358686,31079126,31331314,
%T 37983154,40470296,43452004,58717498,66643660,67991588,77422568,
%U 77995658,79257766,98229376,101553298,123965218,125464136,126241688,130818598,130838170,131305474
%N Numbers b such that b^(2^n) + 3 is prime for n from 0 to 4.
%C Generalized Fermat numbers of the form b^(2^n) + k with k = 3 here.
%t Select[Prime@Range[3, 10^6]-3, PrimeQ[#^2 + 3] && PrimeQ[#^4 + 3] && PrimeQ[#^8 + 3] && PrimeQ[#^16 + 3] &] (* _Giovanni Resta_, May 05 2013 *)
%Y Cf. A070694
%K nonn
%O 1,1
%A _Robin Garcia_, May 05 2013
%E Missing terms a(2) and a(5) and a(12)-a(25) from _Giovanni Resta_, May 05 2013