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A280004
Numbers k such that 9*2^k + 1 is a prime factor of a Fermat number 2^(2^m) + 1 for some m.
2
67, 9431, 461081, 2543551
OFFSET
1,1
LINKS
Eric Weisstein's World of Mathematics, Fermat Number
CROSSREFS
KEYWORD
nonn,hard,more
AUTHOR
STATUS
approved