A269227 Numbers n such that 7^n + 6^(n + 1) is prime.

0, 1, 4, 5, 12, 16, 27, 87, 252, 1052, 1691, 3237, 3669, 16140, 17072, 27932, 70811

Offset

1,3

Comments

a(18) > 10^5.

Links

Table of n, a(n) for n=1..17.

Mathematica

Select[Range[0, 100000], PrimeQ[7^# + 6^(# + 1)] &]

Prog

(Magma) [n: n in [0..500] | IsPrime(7^n+6^(n+1))]; // Vincenzo Librandi, Jul 12 2016
(PARI) is(n)=ispseudoprime(7^n+6^(n+1)) \\ Charles R Greathouse IV, Jun 13 2017

Crossrefs

Cf. A093765.

Sequence in context: A137619 A115375 A212114 * A103650 A131116 A352215

Adjacent sequences: A269224 A269225 A269226 * A269228 A269229 A269230

Keyword

nonn,more

Author

Robert Price, Jul 11 2016

Status

approved