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

1,2

Comments

a(21) > 10^5.

Links

Table of n, a(n) for n=1..20.

Mathematica

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

Prog

(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

Crossrefs

Cf. A093765.

Sequence in context: A157124 A162735 A024675 * A163656 A134678 A100915

Adjacent sequences: A274132 A274133 A274134 * A274136 A274137 A274138

Keyword

nonn,more

Author

Robert Price, Jun 10 2016

Status

approved