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A070592 Largest prime factor of the n-th Fermat number F(n) = 2^(2^n) + 1. 6
3, 5, 17, 257, 65537, 6700417, 67280421310721, 5704689200685129054721, 93461639715357977769163558199606896584051237541638188580280321 (list; graph; refs; listen; history; text; internal format)
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

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Last modified October 14 09:57 EDT 2019. Contains 327995 sequences. (Running on oeis4.)