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Search: id:A027810
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| 1, 12, 63, 224, 630, 1512, 3234, 6336, 11583, 20020, 33033, 52416, 80444, 119952, 174420, 248064, 345933, 474012, 639331, 850080, 1115730, 1447160, 1856790, 2358720, 2968875, 3705156, 4587597, 5638528, 6882744
(list; graph; listen)
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OFFSET
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0,2
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REFERENCES
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A. H. Beiler, Recreations in the Theory of Numbers, Dover, N.Y., 1964, pp. 194-196.
Herbert John Ryser, Combinatorial Mathematics, Carus Mathematical Monographs No. 14, John Wiley and Sons, 1963, pps. 1-8.
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FORMULA
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Number of 11-subsequences of [ 1, n ] with just 5 contiguous pairs; g.f. (1+5x)/(1-x)^7
G.f.: (1+5*x)/(1-x)^7.
C(n+1, 1)*C(n+5, 5) - Zerinvary Lajos (zlaja(AT)freemail.hu), May 26 2005
a(n)=n*(n-1)*(n-2)*(n-3)*(n-4)^2/5!,n=>5 - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 19 2006
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MAPLE
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[seq(n*(n-1)*(n-2)*(n-3)*(n-4)^2/5!, n=5..33)]; - Zerinvary Lajos (zerinvarylajos(AT)yahoo.com), Oct 19 2006
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CROSSREFS
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Partial sums of A051843.
Cf. A093563 ((6, 1) Pascal, column m=6).
Sequence in context: A092224 A085463 A051922 this_sequence A012875 A008425 A105916
Adjacent sequences: A027807 A027808 A027809 this_sequence A027811 A027812 A027813
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KEYWORD
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nonn
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AUTHOR
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thi ngoc dinh (via rkg(AT)cpsc.ucalgary.ca)
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