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A275378
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Number of odd prime factors (with multiplicity) of generalized Fermat number 5^(2^n) + 1.
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2
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OFFSET
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0,4
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LINKS
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FORMULA
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EXAMPLE
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b(n) = (5^(2^n) + 1)/2.
Complete Factorizations
b(0) = 3
b(1) = 13
b(2) = 313
b(3) = 17*11489
b(4) = 2593*29423041
b(5) = 641*75068993*241931001601
b(6) = 769*3666499598977*96132956782643741951225664001
b(7) = 257*23653200983830003298459393*P62
b(8) = 1655809*101199664791578113*4563566430220614493697*
12025702000065183805751513732616276516181800961*P88
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MATHEMATICA
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PROG
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(PARI) a(n) = bigomega(factor((5^(2^n)+1)/2))
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CROSSREFS
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KEYWORD
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nonn,hard,more
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AUTHOR
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STATUS
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approved
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