A070592 Largest prime factor of the n-th Fermat number F(n) = 2^(2^n) + 1.

3, 5, 17, 257, 65537, 6700417, 67280421310721, 5704689200685129054721, 93461639715357977769163558199606896584051237541638188580280321

Offset

0,1

Links

Eric M. Schmidt, Table of n, a(n) for n = 0..11

Eric Weisstein's World of Mathematics, Fermat Number

Prog

(PARI) a(n) = vecmax(factor(2^(2^n) + 1)[, 1]); \\ Michel Marcus, Jul 05 2017

Crossrefs

Cf. A000215, A050922.

Sequence in context: A067387 A050922 A260476 * A254576 A232720 A272061

Adjacent sequences: A070589 A070590 A070591 * A070593 A070594 A070595

Keyword

nonn

Author

Benoit Cloitre, May 12 2002

Extensions

Offset changed by Arkadiusz Wesolowski, Jul 09 2011

Status

approved