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

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

Offset

1,2

Comments

a(8) > 10^5.

Links

Table of n, a(n) for n=1..7.

Example

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

Mathematica

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

Prog

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

Crossrefs

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

Sequence in context: A325296 A052878 A168362 * A076863 A191742 A181082

Adjacent sequences: A274708 A274709 A274710 * A274712 A274713 A274714

Keyword

nonn,more

Author

Robert Price, Jul 03 2016

Status

approved