A217320 Numbers n such that (13^n - 2^n)/11 is prime.

3, 5, 31, 73, 89, 521, 3943, 8719

Offset: 1

Author

Robert Price, Mar 18 2013

Keywords

• hard
• more
• nonn

Comments

All terms are primes.

a(9) > 10^5.

Crossrefs

Cf. A128028, A016054, A210506.

Programs

Mathematica

Select[ Prime[ Range[1, 100000] ], PrimeQ[ (13^# - 2^#)/11 ]& ]

PARI

is(n)=ispseudoprime((13^n-2^n)/11) \\ Charles R Greathouse IV, Jun 06 2017