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

Author

Robert Price, Jul 11 2016

Keywords

• nonn
• more

Comments

a(18) > 10^5.

Crossrefs

Cf. A093765.

Programs

Magma

[n: n in [0..500] | IsPrime(7^n+6^(n+1))]; // Vincenzo Librandi, Jul 12 2016

Mathematica

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

PARI

is(n)=ispseudoprime(7^n+6^(n+1)) \\ Charles R Greathouse IV, Jun 13 2017