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Search: id:A126804
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| A126804 |
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Multiplying n X n integers above n. |
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+0
2
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| 2, 24, 360, 6720, 151200, 3991680, 121080960, 4151347200, 158789030400, 6704425728000, 309744468633600, 15543540607795200, 841941782922240000, 48962152914554880000, 3042648073975910400000, 201220459292273541120000
(list; graph; listen)
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OFFSET
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1,1
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COMMENT
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a(n)=2*A001814(n) - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 03 2007
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FORMULA
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a(n) = (2n)! / (n-1)!
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EXAMPLE
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a(5)= 151200 because five digits above 5: (6, 7, 8, 9, 10), multiplied by five equals 5*(6*7*8*9*10)= 151200
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MAPLE
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a:=n->sum((count(Permutation(2*n+2), size=n+1)), j=0..n): seq(a(n), n=0..15); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), May 03 2007
seq(mul((n+k), k=0..n), n=1..16); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Sep 21 2007
with(combstruct):with(combinat) :bin := {B=Union(Z, Prod(B, B))}: seq (count([B, bin, labeled], size=n)*(n-1), n=2..17); - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Dec 05 2007
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CROSSREFS
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Sequence in context: A043699 A134805 A119702 this_sequence A090114 A081685 A052670
Adjacent sequences: A126801 A126802 A126803 this_sequence A126805 A126806 A126807
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KEYWORD
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nonn
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AUTHOR
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Jonathan R. Love (japanada11(AT)yahoo.ca), Feb 22 2007
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