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A241518
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Number of partitions p of n such that #m(1) = #m(2), where #m(i) = number of numbers in p that have multiplicity i.
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0
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1, 0, 0, 1, 2, 3, 3, 4, 5, 6, 8, 12, 16, 23, 27, 41, 46, 63, 71, 96, 109, 148, 161, 219, 256, 332, 379, 500, 580, 738, 859, 1079, 1250, 1560, 1791, 2220, 2563, 3116, 3595, 4369, 5054, 6080, 7020, 8418, 9729, 11617, 13409, 15911, 18417, 21713, 25078, 29467
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OFFSET
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0,5
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LINKS
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EXAMPLE
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a(6) counts these 3 partitions: 411, 222, 111111.
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MATHEMATICA
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z = 30; u[p_] := Length[DeleteDuplicates[Select[p, Count[p, #] == 1 &]]]; v[p_] := Length[DeleteDuplicates[Select[p, Count[p, #] == 2 &]]]; Table[Count[IntegerPartitions[n], p_ /; u[p] == v[p]], {n, 0, z}]
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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STATUS
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approved
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