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A072953
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a(n)=sum(k=1,n,C(n,n reduced (mod k))).
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0
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1, 2, 5, 7, 22, 25, 79, 124, 276, 444, 1267, 1657, 4435, 7753, 17327, 28309, 72728, 110949, 279663, 476090, 1071672, 1834419, 4512625, 7194685, 17326148, 30229021, 68385742, 117709413, 280395840, 466385404, 1099376097, 1923155966
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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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Observation: lim n -> infinity a(n+2)/a(n) = 4 and it seems that a(n+2)/a(n) < 4 or >4 for infinitely many values of n.
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MATHEMATICA
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Table[Sum[Binomial[n, Mod[n, k]], {k, n}], {n, 40}] (* Harvey P. Dale, Jul 16 2017 *)
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PROG
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(PARI) a(n)=sum(k=1, n, binomial(n, n%k))
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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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