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Search: id:A130760
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| 1, 1, 1, 3, 6, 10, 30, 105, 280, 756, 2520, 6930, 18480, 60060, 180180, 675675, 2162160, 6806800, 24504480, 77597520, 232792560, 888844320, 3259095840, 10708457760, 37479602160, 133855722000
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OFFSET
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0,4
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REFERENCES
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D. E. Knuth, The Art of Computer Programming, vol. 4, section 7.2.1.5, problem 65.
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EXAMPLE
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a(7) = 105 because there are 105 noncrossing set partitions of {1,2,3,4,5,6,7} of type {3,2,1,1}, and all other integer partitions of 7 produce fewer noncrossing set partitions.
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MATHEMATICA
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ncsp[p_] := Falling[Total[p], Length[p] - 1]/Apply[Times, Map[Factorial[Count[p, #1]] &, Range[Max[p]]]]; a[n_] := Max[Map[ncsp, Partitions[n]]]
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CROSSREFS
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Cf. A102356.
Adjacent sequences: A130757 A130758 A130759 this_sequence A130761 A130762 A130763
Sequence in context: A080506 A109163 A109490 this_sequence A001465 A094276 A066245
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KEYWORD
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nonn
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AUTHOR
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Dan Drake (drake(AT)math.umn.edu), Jul 13 2007
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