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A083533
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First difference sequence of A002202. Difference between consecutive possible values for phi(n).
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11
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1, 2, 2, 2, 2, 2, 4, 2, 2, 2, 2, 4, 2, 2, 4, 4, 2, 2, 2, 2, 4, 2, 2, 2, 2, 4, 2, 4, 2, 6, 2, 2, 2, 4, 4, 4, 4, 2, 2, 2, 2, 2, 2, 4, 4, 6, 2, 2, 2, 4, 2, 2, 4, 4, 2, 6, 4, 2, 2, 2, 2, 4, 4, 2, 2, 4, 6, 2, 4, 2, 2, 4, 4, 2, 2, 4, 4, 2, 2, 2, 2, 4, 6, 2, 10, 2, 4, 4, 2, 2, 4, 2, 2, 4, 4, 2, 6, 4, 2, 2, 4, 6, 4, 2, 4
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OFFSET
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1,2
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LINKS
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FORMULA
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EXAMPLE
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12 and 16 are the 7th and 8th possible totient values 12 = phi(13), 16 = phi(17),
while {13,14,15} are impossible ones; thus 16 - 12 = 4 = a(7) = A002202(8) - A002202(7).
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MATHEMATICA
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t=Table[EulerPhi[w], {w, 1, 25000}]; u=Union[%]; Delete[u-RotateRight[u], 1]
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PROG
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(Haskell)
a083533 n = a083533_list !! (n-1)
a083533_list = zipWith (-) (tail a002202_list) a002202_list
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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