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A104679
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a(n) = C(n+5,5)*C(n+10,5).
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1
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252, 2772, 16632, 72072, 252252, 756756, 2018016, 4900896, 11027016, 23279256, 46558512, 88884432, 162954792, 288304632, 494236512, 823727520, 1338557220, 2125943820, 3307023720, 5047562520, 7571343780, 11176745580, 16257084480, 23325382080, 33044291280
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OFFSET
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0,1
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LINKS
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Index entries for linear recurrences with constant coefficients, signature (11,-55,165,-330,462,-462,330,-165,55,-11,1).
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FORMULA
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Sum_{n>=0} 1/a(n) = 5/1134.
Sum_{n>=0} (-1)^n/a(n) = 1280*log(2)/63 - 447047/31752. (End)
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EXAMPLE
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If n=0 then C(0+5,0+0)*C(0+10,5) = C(5,0)*C(10,5) = 1*252 = 252.
If n=4 then C(4+5,4+0)*C(4+10,5) = C(9,4)*C(14,5) = 126*2002 = 252252.
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MATHEMATICA
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Table[Binomial[n+5, n]Binomial[n+10, 5], {n, 0, 20}] (* Harvey P. Dale, Feb 06 2015 *)
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PROG
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(PARI) Vec(252/(1-x)^11 + O(x^100)) \\ Colin Barker, Feb 07 2015
(Magma) [Binomial(n+5, n)*Binomial(n+10, 5): n in [0..30]]; // G. C. Greubel, Nov 25 2017
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CROSSREFS
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KEYWORD
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easy,nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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