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A141902 A triangle sequence of coefficients based on A000984: t(n,m)=(2*n)!/((n - m)!*m!)^2. +0
1
1, 2, 2, 6, 24, 6, 20, 180, 180, 20, 70, 1120, 2520, 1120, 70, 252, 6300, 25200, 25200, 6300, 252, 924, 33264, 207900, 369600, 207900, 33264, 924, 3432, 168168, 1513512, 4204200, 4204200, 1513512, 168168, 3432, 12870, 823680, 10090080, 40360320 (list; graph; listen)
OFFSET

1,2

COMMENT

Row sums are:

{1, 4, 36, 400, 4900, 63504, 853776, 11778624, 165636900, 2363904400, 34134779536}.

Based on reduction of the multinomial:

t(n,m,k,l)=(n+k)1/((n-m)1*m!*(k-l)!*l!)

by symmetry.

The first column is A000984.

FORMULA

t(n,m)=(2*n)!/((n - m)!*m!)^2.

EXAMPLE

{1},

{2, 2},

{6, 24, 6},

{20, 180, 180, 20},

{70, 1120, 2520, 1120, 70},

{252, 6300, 25200, 25200, 6300, 252},

{924, 33264, 207900, 369600, 207900, 33264, 924},

{3432, 168168, 1513512, 4204200, 4204200, 1513512, 168168, 3432},

{12870, 823680, 10090080, 40360320, 63063000, 40360320, 10090080, 823680, 12870},

{48620, 3938220, 63011520, 343062720, 771891120, 771891120, 343062720, 63011520, 3938220, 48620},

{184756, 18475600, 374130900, 2660486400, 8147739600, 11732745024, 8147739600, 2660486400, 374130900,18475600, 184756}

MATHEMATICA

Clear[t, n, m, k, l]; t[n_, m_] = (2*n)!/((n - m)!*m!)^2; Table[Table[t[n, m], {m, 0, n}], {n, 0, 10}]; Flatten[%]

CROSSREFS

Cf. A000984.

Sequence in context: A112478 A138801 A069466 this_sequence A143084 A076741 A093453

Adjacent sequences: A141899 A141900 A141901 this_sequence A141903 A141904 A141905

KEYWORD

nonn,uned

AUTHOR

Roger L. Bagula and Gary W. Adamson (rlbagulatftn(AT)yahoo.com), Sep 13 2008

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Last modified November 27 14:50 EST 2009. Contains 167570 sequences.


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