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Search: id:A072953
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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
1
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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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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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PROGRAM
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(PARI) a(n)=sum(k=1, n, binomial(n, n%k))
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CROSSREFS
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Sequence in context: A143915 A160820 A158357 this_sequence A103060 A103807 A099228
Adjacent sequences: A072950 A072951 A072952 this_sequence A072954 A072955 A072956
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KEYWORD
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nonn
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AUTHOR
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Benoit Cloitre (benoit7848c(AT)orange.fr), Aug 20 2002
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