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Search: id:A090868
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| A090868 |
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Number of partitions of n such that the set of odd parts has only one element. |
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+0
1
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| 1, 1, 3, 2, 6, 5, 11, 8, 20, 15, 32, 24, 51, 39, 80, 58, 119, 90, 175, 130, 255, 190, 361, 268, 508, 379, 706, 522, 967, 722, 1313, 974, 1771, 1317, 2363, 1754, 3131, 2330, 4123, 3058, 5388, 4010, 7001, 5200, 9053, 6731, 11631, 8642, 14878, 11068, 18944
(list; graph; listen)
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OFFSET
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1,3
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FORMULA
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G.f.: Sum_{m>0} x^(2*m-1)/(1-x^(2*m-1))/Product_{m>0} (1-x^(2*m)).
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MATHEMATICA
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first Needs["DiscreteMath`Combinatorica`"], then f[n_] := Count[ Plus @@@ Mod[ Union /@ Partitions[n], 2], 1]; Table[ f[n], {n, 1, 51}] (from Robert G. Wilson v Feb 16 2004)
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CROSSREFS
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Cf. A066897.
Sequence in context: A069159 A085179 A113782 this_sequence A125675 A072787 A107271
Adjacent sequences: A090865 A090866 A090867 this_sequence A090869 A090870 A090871
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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), 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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