A274135 Numbers n such that 6^n + 5^(n+1) is prime.

1, 4, 6, 9, 12, 15, 18, 21, 34, 36, 75, 102, 231, 256, 309, 513, 748, 3789, 12378, 36378

Offset: 1

Author

Robert Price, Jun 10 2016

Keywords

• nonn
• more

Comments

a(21) > 10^5.

Crossrefs

Cf. A093765.

Programs

Mathematica

Select[Range[0,100000], PrimeQ[6^n + 5^(n + 1)] &]

PARI

is(n)=ispseudoprime(6^n + 5^(n+1)) \\ Charles R Greathouse IV, Jun 10 2016

PFGW

ABC2 6^$a + 5^($a+1)
a: from 1 to 100000
Charles R Greathouse IV, Jun 10 2016