A268662 Numbers n such that 5*2^n + 1 is a prime factor of a generalized Fermat number 5^(2^m) + 1 for some m.

7, 15, 25, 39, 55, 75, 85, 127, 1947, 3313, 13165, 23473, 125413, 1282755, 1777515

Offset

1,1

References

Wilfrid Keller, private communication, 2008.

Links

Table of n, a(n) for n=1..15.

Anders Björn and Hans Riesel, Factors of generalized Fermat numbers, Math. Comp. 67 (1998), no. 221, pp. 441-446.

Anders Björn and Hans Riesel, Table errata to “Factors of generalized Fermat numbers”, Math. Comp. 74 (2005), no. 252, p. 2099.

Anders Björn and Hans Riesel, Table errata 2 to "Factors of generalized Fermat numbers", Math. Comp. 80 (2011), pp. 1865-1866.

C. K. Caldwell, Top Twenty page, Generalized Fermat Divisors (base=5)

OEIS Wiki, Generalized Fermat numbers

Crossrefs

Cf. A199591, A268661, A268663, A226366, A268664, A268657, A268658, A204620, A268659, A268660. Subsequence of A002254.

Sequence in context: A082111 A323483 A236582 * A297954 A298577 A299569

Adjacent sequences: A268659 A268660 A268661 * A268663 A268664 A268665

Keyword

nonn,hard,more

Author

Arkadiusz Wesolowski, Feb 10 2016

Status

approved