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A238798
Least odd k such that k*2^n + 1 is a prime factor of a Fermat number 2^(2^m) + 1 for some m, or 0 if no such value exists.
0
0, 1, 1, 0, 1, 0, 0, 5, 1, 116503103764643, 0, 604944512477, 11131, 39, 7
OFFSET
0,8
COMMENTS
The sequence continues: a(15) = ?, 1, 17753925353, a(18) = ?, 1575, 13, 579, a(22) = ?
LINKS
Fermat factoring status, Prime factors of Fermat numbers
FermatSearch, Home page
Eric Weisstein's World of Mathematics, Fermat Number
CROSSREFS
Sequence in context: A009826 A255855 A255858 * A112871 A249421 A359226
KEYWORD
nonn,hard
AUTHOR
STATUS
approved