A274711 Numbers n such that 5^n + 4^(n+1) is prime.

0, 2, 6, 34, 282, 3662, 87206

Offset: 1

Author

Robert Price, Jul 03 2016

Keywords

• nonn
• more

Comments

a(8) > 10^5.

Examples

			6 is a member since 5^6 + 4^7 = 15625 + 16384 = 32009 which is a prime number.
		

Crossrefs

Cf. A093713, A082103, A093717, A093793, A096185, A093794, A093795, A096186, A271883, A271884.

Programs

Mathematica

Select[Range[0, 100000], PrimeQ[5^# + 4^(# + 1)] &]

PARI

lista(nn) = for(n=0, nn, if(ispseudoprime(5^n + 4^(n+1)), print1(n, ", "))); \\ Altug Alkan, Jul 03 2016