A282946 - OEIS

A282946

Numbers k such that 5*2^k + 1 is a prime factor of a generalized Fermat number 11^(2^m) + 1 for some m.

15, 1947, 125413, 240937

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OFFSET

1,1

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.

MATHEMATICA

lst = {}; Do[p = 5*2^n + 1; If[PrimeQ[p] && IntegerQ@Log[2, MultiplicativeOrder[11, p]], AppendTo[lst, n]], {n, 1, 1947, 2}]; lst

CROSSREFS

Subsequence of A002254.

KEYWORD

nonn,hard,more

AUTHOR

STATUS

approved