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A182411
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Triangle T(n,k) = (2*k)!*(2*n)!/(k!*n!*(k+n)!) with k=0..n, read by rows.
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2
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1, 2, 2, 6, 4, 6, 20, 10, 12, 20, 70, 28, 28, 40, 70, 252, 84, 72, 90, 140, 252, 924, 264, 198, 220, 308, 504, 924, 3432, 858, 572, 572, 728, 1092, 1848, 3432, 12870, 2860, 1716, 1560, 1820, 2520, 3960, 6864, 12870, 48620, 9724, 5304, 4420, 4760, 6120, 8976
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OFFSET
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0,2
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COMMENTS
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This is a companion to the triangle A068555.
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REFERENCES
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Umberto Scarpis, Sui numeri primi e sui problemi dell'analisi indeterminata in Questioni riguardanti le matematiche elementari, Nicola Zanichelli Editore (1924-1927, third edition), page 11.
J. V. Uspensky and M. A. Heaslet, Elementary Number Theory, McGraw-Hill, NY, 1939, p. 103.
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LINKS
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EXAMPLE
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Triangle begins:
1;
2, 2;
6, 4, 6;
20, 10, 12, 20;
70, 28, 28, 40, 70;
252, 84, 72, 90, 140, 252;
924, 264, 198, 220, 308, 504, 924;
3432, 858, 572, 572, 728, 1092, 1848, 3432;
12870, 2860, 1716, 1560, 1820, 2520, 3960, 6864, 12870;
48620, 9724, 5304, 4420, 4760, 6120, 8976, 14586, 25740, 48620;
...
Sum_{k=0..8} T(8,k) = 12870 + 2860 + 1716 + 1560 + 1820 + 2520 + 3960 + 6864 + 12870 = 2*A132310(7) + A000984(8) = 2*17085 + 12870 = 47040.
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MATHEMATICA
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Flatten[Table[Table[(2 k)! ((2 n)!/(k! n! (k + n)!)), {k, 0, n}], {n, 0, 9}]]
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PROG
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(Magma)
[Factorial(2*k)*Factorial(2*n)/(Factorial(k)*Factorial(n)*Factorial(k+n)): k in [0..n], n in [0..9]];
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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