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A027775
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a(n) = (n+1)*binomial(n+1, 15).
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2
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15, 256, 2312, 14688, 73644, 310080, 1139544, 3751968, 11277222, 31380096, 81719000, 200880160, 469364220, 1048380480, 2249204040, 4653525600, 9316746045, 18103127040, 34226224560, 63102895680, 113678010600, 200444492160, 346475391120, 587908889280
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OFFSET
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14,1
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COMMENTS
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Number of 17-subsequences of [ 1, n ] with just 1 contiguous pair.
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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.: x^14*(15+x)/(1-x)^17.
Sum_{n>=14} 1/a(n) = 5*Pi^2/2 - 106497287263/4328644320.
Sum_{n>=14} (-1)^n/a(n) = 5*Pi^2/4 + 115552256*log(2)/3003 - 16500694723831/618377760. (End)
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MATHEMATICA
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Table[(n+1)Binomial[n+1, 15], {n, 14, 40}] (* Harvey P. Dale, Jul 26 2011 *)
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PROG
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CROSSREFS
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KEYWORD
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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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