A225818 Numbers n such that (19^n + 18^n)/37 is prime.

5, 223, 311, 54547

Offset: 1

Author

Robert Price, Aug 26 2013

Keywords

• hard
• nonn
• more

Comments

All terms are primes.

a(5) > 10^5. - Robert Price, Oct 03 2013

Crossrefs

Cf. A227170, A221637, A228558, A227046.

Programs

Mathematica

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (19^# + 18^#)/37 ]& ]

PARI

is(n)=ispseudoprime((19^n+18^n)/37) \\ Charles R Greathouse IV, Jun 06 2017