A182331 Primes of the form 6^k + 1.

2, 7, 37, 1297

Offset: 1

Author

Alex Ratushnyak, Apr 25 2012

Keywords

• nonn

Comments

No other terms for k < 3000. - T. D. Noe, Apr 25 2012

Apart from the first term, the exponents must be powers of two. Like Fermat primes, there are probably only finitely many terms. No more terms for k < 2^28 = 268435456. - Charles R Greathouse IV, Jul 16 2012

Links

• Wilfrid Keller, Prime factors of generalized Fermat numbers F_m(6) and complete factoring status

Crossrefs

Cf. A057735, A182330.

Programs

Mathematica

Select[Table[6^n + 1, {n, 0, 100}], PrimeQ] (* T. D. Noe, Apr 25 2012 *)

PFGW

ABC2 6^(2^$a)+1
a: from 0 to 18
// Charles R Greathouse IV, Jul 16 2012