A287842 Primes of the form (1 + x)^(2^y) + x^(2^y) where x is a divisor of y.

5, 17, 97, 257, 65537

Offset

1,1

Links

Table of n, a(n) for n=1..5.

Juri-Stepan Gerasimov, x^(y + 1) - y^x, SeqFan list, Aug 18 2014.

Eric Weisstein's World of Mathematics, Fermat Prime.

Example

97 is in this sequence because (1 + 2)^(2^2) + 2^(2^2) = 97 is prime and 2 is a divisor of 2.

Mathematica

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 *)

Crossrefs

Subsequence of A285886.

Cf. A019434.

Sequence in context: A367921 A180382 A250717 * A254759 A139390 A145824

Adjacent sequences: A287839 A287840 A287841 * A287843 A287844 A287845

Keyword

nonn,more

Author

Juri-Stepan Gerasimov, Jun 01 2017

Status

approved