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A156700
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Number of partitions of the set of odd numbers {1, 3, 5, ..., 4*n-1} in two subsets with equal sum.
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1
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0, 1, 1, 4, 10, 34, 103, 346, 1153, 3965, 13746, 48396, 171835, 615966, 2223755, 8082457, 29543309, 108545916, 400623807, 1484716135, 5522723344, 20612084010, 77164686511, 289688970195, 1090342139349, 4113620233260, 15553877949800, 58930127470164
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,4
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LINKS
| Alois P. Heinz, Table of n, a(n) for n = 1..400
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EXAMPLE
| For n=2: {1,7}U{3,5}. For n=3: {1,3,5,9}U{7,11}. For n=4: {1,3,13,15}U{5,7,9,11}, {1,5,11,15}U{3,7,9,13}, {1,7,9,15}U{3,5,11,13}, {3,5,9,15}U{1,7,11,13}.
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MAPLE
| b:= proc() option remember; local i, j, t; `if` (args[1]=0, `if` (nargs=2, 1, b(args[t] $t=2..nargs)), add (`if` (args[j] -args[nargs] <0, 0, b(sort ([seq (args[i] -`if` (i=j, args[nargs], 0), i=1..nargs-1)])[], args[nargs]-2)), j=1..nargs-1)) end: a:= n-> b((2*n^2)$2, 4*n-1)/2: seq (a(n), n=1..40); # Alois P. Heinz, Sep 06 2009
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CROSSREFS
| Sequence in context: A140725 A005630 A100507 * A182645 A006343 A149173
Adjacent sequences: A156697 A156698 A156699 * A156701 A156702 A156703
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KEYWORD
| nonn
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AUTHOR
| Wim Couwenberg (wim.couwenberg(AT)gmail.com), Feb 13 2009
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EXTENSIONS
| Extended beyond a(18) by Alois P. Heinz (heinz(AT)hs-heilbronn.de), Sep 06 2009
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