A224501 Numbers n such that (11^n + 4^n)/15 is prime.

7, 53, 67, 71, 443, 26497

Offset

1,1

Comments

All terms are prime.

a(7) > 10^5.

Links

Table of n, a(n) for n=1..6.

Mathematica

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (11^# + 4^#)/15 ]& ]

Prog

(PARI) is(n)=ispseudoprime((11^n+4^n)/15) \\ Charles R Greathouse IV, Jun 06 2017

Crossrefs

Cf. A057178, A128341, A181141, A187819, A217095.

Sequence in context: A300875 A301485 A357362 * A241487 A236688 A239941

Adjacent sequences: A224498 A224499 A224500 * A224502 A224503 A224504

Keyword

hard,nonn,more

Author

Robert Price, Apr 08 2013

Status

approved