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Search: id:A090867
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| A090867 |
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Number of partitions of n such that the set of even parts has only one element. |
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+0
1
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| 0, 1, 1, 3, 4, 6, 9, 13, 18, 23, 32, 42, 55, 69, 89, 112, 141, 175, 217, 266, 326, 396, 480, 581, 697, 834, 996, 1183, 1402, 1660, 1954, 2297, 2694, 3150, 3674, 4280, 4970, 5762, 6669, 7701, 8876, 10219, 11737, 13460, 15418, 17628, 20125, 22951, 26128, 29709
(list; graph; listen)
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OFFSET
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1,4
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FORMULA
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G.f.: Sum_{m>0} x^(2*m)/(1-x^(2*m))/Product_{m>0} (1-x^(2*m-1)).
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MATHEMATICA
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first Needs["DiscreteMath`Combinatorica`"], then f[n_] := Count[ Plus @@@ Mod[ Union /@ Partitions[n] + 1, 2], 1]; Table[ f[n], {n, 1, 50}] (from Robert G. Wilson v Feb 16 2004)
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CROSSREFS
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Sequence in context: A096846 A140570 A032720 this_sequence A005626 A030712 A025000
Adjacent sequences: A090864 A090865 A090866 this_sequence A090868 A090869 A090870
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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.yu), Feb 12 2004
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EXTENSIONS
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More terms from Robert G. Wilson v (rgwv(AT)rgwv.com), Feb 16 2004
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