A225097 Numbers n such that (13^n + 12^n)/25 is prime.

3, 11, 13, 43, 67, 109, 15101, 43997

Offset: 1

Author

Robert Price, Apr 27 2013

Keywords

• hard
• nonn
• more

Comments

All terms are prime.

a(9) > 10^5.

Crossrefs

Cf. A057179, A128071, A128342, A213216, A224984.

Programs

Mathematica

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (13^# + 12^#)/25 ]& ]

PARI

is(n)=ispseudoprime((13^n+12^n)/25) \\ Charles R Greathouse IV, May 22 2017