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Search: id:A064670
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| A064670 |
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Triangle T(n,k) (1 <= k <= n) where the first column (T(n,1)) is the sequence of secant numbers A000364. |
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| 1, 1, 4, 5, 20, 36, 61, 244, 504, 576, 1385, 5540, 11916, 17280, 14400, 50521, 202084, 442224, 697536, 792000, 518400, 2702765, 10811060, 23870196, 39202560, 50198400, 47174400, 25401600, 199360981, 797443924, 1769923944
(list; table; graph; listen)
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OFFSET
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1,3
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COMMENT
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Replacing m*m by m*(m+1) in the formula, the first column gives the tangent numbers A000182
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FORMULA
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T(n+1, m) = m*m*Sum_{k = m-1, n} T(n, k) (T(n, 0) = 0)
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EXAMPLE
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T(4,3) = 9*(T(3,2) + (T(3,3)) = 9*(20+36) = 504
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CROSSREFS
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Cf. A064190, A000182, A000354.
Sequence in context: A163141 A059182 A027958 this_sequence A119283 A151499 A057781
Adjacent sequences: A064667 A064668 A064669 this_sequence A064671 A064672 A064673
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KEYWORD
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easy,nice,nonn,tabl
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AUTHOR
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Jose L. Arregui (arregui(AT)posta.unizar.es), Oct 09 2001
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EXTENSIONS
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More terms from Philippe DELEHAM (kolotoko(AT)wanadoo.fr), Sep 22 2005
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