%I #9 Aug 04 2019 04:41:24
%S 54,3076,11796
%N Numbers k such that 7^k + k^7 is prime.
%C a(4) > 110000.
%Y Cf. A001596, A114974, A309421.
%K nonn,bref,more,hard
%O 1,1
%A _Hugo Pfoertner_, Jul 30 2019
