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A070592 Largest prime factor of the n-th Fermat number F(n) = 2^(2^n) + 1. 5
3, 5, 17, 257, 65537, 6700417, 67280421310721, 5704689200685129054721, 93461639715357977769163558199606896584051237541638188580280321 (list; graph; refs; listen; history; text; internal format)
OFFSET
0,1
LINKS
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
Sequence in context: A067387 A050922 A260476 * A254576 A232720 A272061
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 February 27 19:38 EST 2024. Contains 370378 sequences. (Running on oeis4.)