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Search: id:A002084
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| A002084 |
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Expansion of sinh x / cos x.
(Formerly M3667 N1493)
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+0
9
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| 1, 4, 36, 624, 18256, 814144, 51475776, 4381112064, 482962852096, 66942218896384, 11394877025289216, 2336793875186479104, 568240131312188379136
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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Gandhi, J. M.; The coefficients of sinh x/ cos x. Canad. Math. Bull. 13 1970 305-310.
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LINKS
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T. D. Noe, Table of n, a(n) for n=0..50
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FORMULA
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E.g.f.: sinh(x)/cos(x).
a(n) = Sum_{k, 0<=k<=n} binomial(2n+1, 2k+1)*A000364(n-k) = Sum_{k, 0<=k<=n} A103327(n, k)*A000324(n-k) = Sum_{k, 0<=k<=n} (-1)^(n-k)*A104033(n, k) . - Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Aug 27 2005
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EXAMPLE
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x+2/3*x^3+3/10*x^5+13/105*x^7+163/3240*x^9+...
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CROSSREFS
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Sequence in context: A001044 A086879 A002761 this_sequence A135867 A029989 A126152
Adjacent sequences: A002081 A002082 A002083 this_sequence A002085 A002086 A002087
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KEYWORD
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nonn,easy
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AUTHOR
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njas
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