A268065 Integers k such that 2^k + 3^k + 5^k + k is prime.

0, 1, 3, 7, 19, 33, 1363, 6663

Offset: 1

Author

Emre APARI, Jan 25 2016

Keywords

• nonn
• more

Comments

a(8), if it exists, is greater than 30000. - Vaclav Kotesovec, Jan 26 2016

a(8), if it exists, is greater than 100000. - Michael S. Branicky, Dec 01 2024

Examples

			k=3: 2^3+3^3+5^3+3 = 163.
		

Crossrefs

Cf. A076515, A268067.

Programs

Mathematica

Select[Range[0, 2000], PrimeQ[2^# + 3^# + 5^# + #] &] (* Vaclav Kotesovec, Jan 25 2016 *)

PARI

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

Extensions

a(7) from Vaclav Kotesovec, Jan 25 2016