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Search: id:A007012
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| A007012 |
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a(n) is number of k for which C(n,k) is not divisible by n. (Formerly M0248)
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+0 3
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| 1, 0, 2, 2, 3, 2, 5, 2, 5, 4, 5, 2, 8, 2, 9, 8, 9, 2, 9, 2, 11, 8, 9, 2, 15, 6, 9, 10, 15, 2, 20, 2, 17, 8, 5, 10, 15, 2, 9, 10, 19, 2, 23, 2, 19, 20, 17, 2, 29, 8, 17, 20, 19, 2, 29, 10, 24, 8, 17, 2, 35, 2, 33, 18, 33, 16, 19, 2, 11, 20, 27, 2, 33, 2, 9, 30, 19, 16, 41, 2, 31, 28, 9, 2, 32, 16
(list; graph; listen)
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OFFSET
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0,3
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COMMENT
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The number of nonzero terms in the polynomial (1+x)^n (mod n). Note that n is prime iff a(n)=2. - T. D. Noe (noe(AT)sspectra.com), Feb 23 2006
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REFERENCES
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N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).
J. H. Conway, personal communication.
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LINKS
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T. D. Noe, Table of n, a(n) for n = 0..1000
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FORMULA
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a(n)=n+1-A020475(n) - T. D. Noe (noe(AT)sspectra.com), Feb 23 2006
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MATHEMATICA
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Prepend[ Array[ Length[ Select[ Table[ Binomial[ #, k ]/#, {k, 0, #} ], !IntegerQ[ # ]& ] ]&, 100 ], 1 ]
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CROSSREFS
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Sequence in context: A100565 A010846 A073023 this_sequence A062830 A164941 A115119
Adjacent sequences: A007009 A007010 A007011 this_sequence A007013 A007014 A007015
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KEYWORD
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nonn
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AUTHOR
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N. J. A. Sloane (njas(AT)research.att.com).
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