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A140712
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Number of white corners in all permutations of {1,2,...,n} (for definition see the Eriksson-Linusson references).
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2
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0, 1, 6, 37, 256, 2000, 17520, 170520, 1827840, 21409920, 272160000, 3732220800, 54925516800, 863480217600, 14442536908800, 256086230400000, 4798293147648000, 94731418349568000, 1965528727658496000
(list; graph; refs; listen; history; internal format)
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OFFSET
| 1,3
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REFERENCES
| K. Eriksson and S. Linusson. Combinatorics of Fulton's essential set. Duke Mathematical Journal 85(1):61-76, 1996.
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LINKS
| K. Eriksson and S. Linusson, The size of Fulton's essential set, Electronic J. Combinatorics, Vol. 2, #R6, 1995.
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FORMULA
| a(n)=Sum(k*A140711(n,k),k=0..n-1).
a(n)=(n-1)![binom(n-1,3)+6*binom(n,2)]/6=(n-1)!*(n-1)*(n^2+13n+6)/36.
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MAPLE
| seq((1/36)*(n-1)*factorial(n-1)*(n^2+13*n+6), n=1..20);
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PROG
| (PARI) a(n)=(n^2+13*n+6)*(n-1)*(n-1)!/36 \\ Charles R Greathouse IV, Oct 31 2011
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CROSSREFS
| Cf. A000142, A140711.
Sequence in context: A080954 A073013 A192238 * A079751 A088312 A012364
Adjacent sequences: A140709 A140710 A140711 * A140713 A140714 A140715
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KEYWORD
| nonn,easy
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AUTHOR
| Emeric Deutsch (deutsch(AT)duke.poly.edu), May 28 2008
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