A222265 Numbers n such that (13^n + 2^n)/15 is prime.

7, 31, 103, 223, 503, 1171, 1973, 4111, 4729

Offset

1,1

Comments

All terms are prime.

a(10) > 10^5.

Links

Table of n, a(n) for n=1..9.

Mathematica

Select[Prime[Range[1, 100000]], PrimeQ[(13^# + 2^#)/15]&]

Prog

(PARI) forprime(p=3, 10^6, if(ispseudoprime((13^p + 2^p)/15), print1(p, ", ") ) ); \\ Joerg Arndt, Jul 29 2013

Crossrefs

Cf. A125956, A125957, A057159, A128071, A213176.

Sequence in context: A055899 A218956 A139876 * A107392 A054497 A235593

Adjacent sequences: A222262 A222263 A222264 * A222266 A222267 A222268

Keyword

nonn,hard,more

Author

Robert Price, May 05 2013

Extensions

Removed incorrect first term of "2".

Status

approved