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A091437
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Number of bipartite partitions of ceil(n/2) white objects and floor(n/2) black ones.
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2
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1, 1, 2, 4, 9, 16, 31, 57, 109, 189, 339, 589, 1043, 1752, 2998, 4987, 8406, 13715, 22652, 36535, 59521, 94664, 151958, 239241, 379693, 591271, 927622, 1431608, 2224235, 3402259, 5236586, 7947530, 12130780, 18272221, 27669593, 41393154
(list; graph; refs; listen; history; internal format)
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OFFSET
| 0,3
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MATHEMATICA
| max = 35; se = Series[ Sum[ Log[1 - x^(n - k)*y^k], {n, 1, 2max}, {k, 0, n}], {x, 0, 2max}, {y, 0, 2max}]; coes = CoefficientList[ Series[ Exp[-se], {x, 0, 2max}, {y, 0, 2max}], {x, y}]; a[n_] := coes[[ Ceiling[(n+2)/2], Floor[(n+2)/2] ]]; Table[a[n], {n, 0, max} ](* From Jean-François Alcover, Dec 06 2011 *)
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CROSSREFS
| a(n) = A054225(n, [n/2]). Cf. A002774, A005380.
Sequence in context: A034452 A034449 A082894 * A131337 A062791 A203320
Adjacent sequences: A091434 A091435 A091436 * A091438 A091439 A091440
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KEYWORD
| nonn
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AUTHOR
| Christian G. Bower (bowerc(AT)usa.net), Jan 08 2004
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