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A047922
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Triangle of numbers a(n,k) = number of terms in n X n determinant with 2 adjacent diagonals of k and k-1 0's (0<=k<=n).
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4
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1, 1, 0, 2, 1, 0, 6, 4, 1, 1, 24, 18, 8, 5, 3, 120, 96, 54, 34, 23, 16, 720, 600, 384, 258, 182, 131, 96, 5040, 4320, 3000, 2136, 1566, 1168, 883, 675, 40320, 35280, 25920, 19320, 14664, 11274, 8756, 6859, 5413, 362880, 322560, 246960, 190800, 149160
(list; table; graph; refs; listen; history; internal format)
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OFFSET
| 0,4
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REFERENCES
| J. D. H. Dickson, Discussion of two double series arising from the number of terms in determinants of certain forms, Proc. London Math. Soc., 10 (1879), 12.
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FORMULA
| Right diagonal is A000271; other entries given by a(n, k)=a(n, k+1)+2a(n-1, k)+a(n-2, k-1).
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EXAMPLE
| 1; 1 0; 2 1 0; 6 4 1 1; ...
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CROSSREFS
| Columns give A000142, A001563, A002775, A002776. Cf. A047920.
Sequence in context: A127631 A122538 A090238 * A021830 A111184 A111596
Adjacent sequences: A047919 A047920 A047921 * A047923 A047924 A047925
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KEYWORD
| nonn,tabl,nice,easy
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AUTHOR
| N. J. A. Sloane (njas(AT)research.att.com).
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EXTENSIONS
| More terms from Larry Reeves (larryr(AT)acm.org), Sep 29 2000
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