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A053285
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Totient of 2^n+1.
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12
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1, 2, 4, 6, 16, 20, 48, 84, 256, 324, 800, 1364, 3840, 5460, 12544, 19800, 65536, 87380, 186624, 349524, 986880, 1365336, 3345408, 5592404, 16515072, 20250000, 52306176, 84768120, 252645120, 351847488, 760320000, 1431655764, 4288266240
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OFFSET
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0,2
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LINKS
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FORMULA
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EXAMPLE
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It is a power of 2 iff n is a Fermat prime.
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MAPLE
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seq(numtheory:-phi(2^n+1), n=0..50); # Robert Israel, Aug 12 2015
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MATHEMATICA
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PROG
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(PARI) vector(40, n, eulerphi(2^n+1)) \\ Michel Marcus, Aug 12 2015
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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