A224507 Numbers n such that (17^n + 2^n)/19 is prime.

5, 7, 113, 193, 211, 701, 797, 907, 4153

Offset: 1

Author

Robert Price, Jul 20 2013

Keywords

• nonn
• hard
• more

Comments

All terms are prime.

a(10) > 10^5.

Crossrefs

Cf. A057183, A125957, A222265, A225191, A227046.

Programs

Mathematica

Select[Prime[Range[1, 100000]], PrimeQ[(17^# + 2^#)/19]&]

PARI

is(n)=ispseudoprime((17^n+2^n)/19) \\ Charles R Greathouse IV, Jun 06 2017