%I #22 Nov 04 2024 01:44:18
%S 1,17,1295,63445
%N Numbers k such that 1 + 2^k + 3^k + 5^k is prime.
%C a(4), if it exists, is greater than 50000. - _Michael S. Branicky_, Mar 31 2023
%t Select[Range[0, 2000], PrimeQ[1 + 2^# + 3^# + 5^#] &]
%o (PARI) lista(nn) = for(n=0, nn, if(ispseudoprime(1 + 2^n + 3^n + 5^n), print1(n, ", "))); \\ _Altug Alkan_, Jan 25 2016
%Y Cf. A076515, A268064, A268065.
%K nonn,more
%O 1,2
%A _Vaclav Kotesovec_, Jan 25 2016
%E a(4) from _Michael S. Branicky_, Nov 03 2024