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A140711
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Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} having k white corners (0<=k<=n-1; for definition see the Eriksson-Linusson references).
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2
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1, 1, 1, 1, 4, 1, 1, 10, 12, 1, 1, 20, 62, 36, 1
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 1,5
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COMMENTS
| Sum of entries in row n is n! (A000142).
Sum(k*T(n,k),k=0..n-1)=A140712(n).
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REFERENCES
| K. Eriksson and S. Linusson, The size of Fulton's essential set, Electronic J. Combinatorics, Vol. 2, #R6, 1995.
K. Eriksson and S. Linusson. Combinatorics of Fulton's essential set. Duke Mathematical Journal 85(1):61-76, 1996.
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EXAMPLE
| Triangle starts:
1;
1,1;
1,4,1;
1,10,12,1;
1,20,62,36,1;
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CROSSREFS
| Cf. A000142, A140712.
Sequence in context: A202924 A142595 A174669 * A164366 A121692 A145271
Adjacent sequences: A140708 A140709 A140710 * A140712 A140713 A140714
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KEYWORD
| more,nonn,tabl
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AUTHOR
| Emeric Deutsch (deutsch(AT)duke.poly.edu), May 28 2008
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