A227173 Numbers k such that (138^k + 137^k)/275 is prime.

7, 13, 2371, 2791, 2999, 4621, 8819, 21563

Offset: 1

Author

Jean-Louis Charton, Jul 03 2013

Keywords

• hard
• nonn
• more

Comments

All terms are prime.

Crossrefs

Cf. A000978, A057469, A128066, A128335, A128336, A187805, A181141, A187819, A217095.

Programs

PARI

is(n)=ispseudoprime((138^n+137^n)/275) \\ Charles R Greathouse IV, Jun 13 2017

Extensions

a(8) from Tyler Busby, Mar 19 2023