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A320734
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Number of partitions of n with three sorts of part 1 which are introduced in ascending order.
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4
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1, 1, 3, 7, 19, 52, 151, 442, 1314, 3921, 11737, 35171, 105464, 316318, 948863, 2846461, 8539221, 25617443, 76852054, 230555794, 691666924, 2075000173, 6224999772, 18674998357, 56024993883, 168074980137, 504224938548, 1512674813304, 4538024437036
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OFFSET
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0,3
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LINKS
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MAPLE
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b:= proc(n, i) option remember; `if`(n=0 or i<2, add(
Stirling2(n, j), j=0..3), add(b(n-i*j, i-1), j=0..n/i))
end:
a:= n-> b(n$2):
seq(a(n), n=0..40);
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MATHEMATICA
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b[n_, i_] := b[n, i] = If[n == 0 || i < 2, Sum[StirlingS2[n, j], {j, 0, 3}], Sum[b[n - i j, i - 1], {j, 0, n/i}]];
a[n_] := b[n, n];
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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