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%I #18 Feb 27 2024 01:25:57
%S 5,17,97,257,65537
%N Primes of the form (1 + x)^(2^y) + x^(2^y) where x is a divisor of y.
%H Juri-Stepan Gerasimov, <a href="http://list.seqfan.eu/pipermail/seqfan/2014-August/028149.html">x^(y + 1) - y^x</a>, SeqFan list, Aug 18 2014.
%H Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/FermatPrime.html">Fermat Prime</a>.
%e 97 is in this sequence because (1 + 2)^(2^2) + 2^(2^2) = 97 is prime and 2 is a divisor of 2.
%t Sort@ Flatten@ Table[Function[{x, y}, Select[(1 + x)^(2^y) + x^(2^y), PrimeQ]] @@ {Divisors@ #, #} &@ n, {n, 12}] (* _Michael De Vlieger_, Jun 01 2017 *)
%Y Subsequence of A285886.
%Y Cf. A019434.
%K nonn,more
%O 1,1
%A _Juri-Stepan Gerasimov_, Jun 01 2017
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