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A105944
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a(n) = C(n+8,n)*C(n+11,8).
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0
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165, 4455, 57915, 495495, 3185325, 16563690, 73002930, 281582730, 972740340, 3062330700, 8904315420, 24168856140, 61764854580, 149660993790, 345855237750, 766005304350, 1632800780325, 3361648665375, 6705510829875, 12993932469375, 24518985616125
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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 (17,-136,680,-2380,6188,-12376,19448,-24310,24310,-19448,12376,-6188,2380,-680,136,-17,1).
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FORMULA
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G.f.: -165*(x+1)*(x^4+9*x^3+19*x^2+9*x+1) / (x-1)^17. - Colin Barker, Jan 28 2013
Sum_{n>=0} 1/a(n) = 1493776559/14175 - 32032*Pi^2/3.
Sum_{n>=0} (-1)^n/a(n) = 112*Pi^2 - 1740989/1575. (End)
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EXAMPLE
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If n=0 then C(0+8,0)*C(0+11,8) = C(8,0)*C(11,8) = 1*165 = 165.
If n=4 then C(4+8,4)*C(4+11,8) = C(12,4)*C(15,8) = 495*6435 = 3185325.
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MATHEMATICA
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Table[Binomial[n+8, n]Binomial[n+11, 8], {n, 0, 30}] (* Harvey P. Dale, Apr 26 2018 *)
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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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