A268067 Numbers k such that 1 + 2^k + 3^k + 5^k is prime.

1, 17, 1295, 63445

Offset: 1

Author

Vaclav Kotesovec, Jan 25 2016

Keywords

• nonn
• more

Comments

a(4), if it exists, is greater than 50000. - Michael S. Branicky, Mar 31 2023

Crossrefs

Cf. A076515, A268064, A268065.

Programs

Mathematica

Select[Range[0, 2000], PrimeQ[1 + 2^# + 3^# + 5^#] &]

PARI

lista(nn) = for(n=0, nn, if(ispseudoprime(1 + 2^n + 3^n + 5^n), print1(n, ", "))); \\ Altug Alkan, Jan 25 2016

Extensions

a(4) from Michael S. Branicky, Nov 03 2024