A224984 Numbers n such that (14^n + 13^n)/27 is prime.

7, 13, 311, 1637, 4363, 10433, 41669, 45631

Offset: 1

Author

Robert Price, Apr 22 2013

Keywords

• hard
• nonn
• more

Comments

All terms are prime.

a(9) > 10^5.

Crossrefs

Cf. A057180, A128072, A128343, A181141, A187819, A217095, A185239, A213216.

Programs

Mathematica

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (14^# + 13^#)/27 ]& ]

PARI

forprime(p=3,10^6, if(ispseudoprime((14^p + 13^p)/27), print1(p,", ") ) ); \\ Joerg Arndt, Jul 29 2013

Extensions

Removed incorrect first term of "2".