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Search: id:A130222
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| A130222 |
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Number of partitions of 2n-set in which number of blocks of size 2k-1 is even (or zero) for every k. |
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+0
1
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| 1, 2, 11, 117, 2116, 54233, 1822053, 76771684, 3922196627, 238355654605, 16936961517144, 1387902030575371, 129757092644981529, 13704639448111317852, 1621528608322059614411, 213338281602779271672663
(list; graph; listen)
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OFFSET
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0,2
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FORMULA
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E.g.f.: exp(cosh(x)-1)*Product_{k>0} cosh(x^(2*k-1)/(2*k-1)!).
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MAPLE
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A := proc(n) exp( cosh(x)-1) *mul (cosh (x^(2*k-1)/ (2*k-1)!), k=1..n) end: a := n-> coeff (series (A(n), x, 2*n+1), x, 2*n) *(2*n)!: seq (a(n), n=0..20); [From Alois P. Heinz (heinz(AT)hs-heilbronn.de), Sep 29 2008]
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CROSSREFS
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Cf. A102759.
Sequence in context: A145163 A069574 A090534 this_sequence A057076 A118794 A155928
Adjacent sequences: A130219 A130220 A130221 this_sequence A130223 A130224 A130225
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KEYWORD
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easy,nonn
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AUTHOR
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Vladeta Jovovic (vladeta(AT)eunet.rs), Aug 05 2007, Aug 05 2007
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EXTENSIONS
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More terms from Alois P. Heinz (heinz(AT)hs-heilbronn.de), Sep 29 2008
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