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

Author

Arkadiusz Wesolowski, Feb 10 2016

Keywords

• nonn
• hard
• more

References

• Wilfrid Keller, private communication, 2008.

Links

• 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.