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A165618
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a(n) = binomial(n+8,8) - 1.
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1
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0, 8, 44, 164, 494, 1286, 3002, 6434, 12869, 24309, 43757, 75581, 125969, 203489, 319769, 490313, 735470, 1081574, 1562274, 2220074, 3108104, 4292144, 5852924, 7888724, 10518299, 13884155, 18156203, 23535819, 30260339, 38608019, 48903491
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OFFSET
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0,2
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LINKS
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FORMULA
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a(n) = binomial(n+8,8) - 1 = A000581(n+8) - 1.
a(n) = Sum_{r=1..n} binomial(8,r)*binomial(n,r).
a(n) = n(n+9)(n^6 + 27n^5 + 303n^4 + 1809n^3 + 6168n^2 + 11772n + 12176)/40320.
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MATHEMATICA
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Table[ -1 + Binomial[n + 8, 8], {n, 0, 30}]
LinearRecurrence[{9, -36, 84, -126, 126, -84, 36, -9, 1}, {0, 8, 44, 164, 494, 1286, 3002, 6434, 12869}, 40] (* Harvey P. Dale, Nov 18 2013 *)
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PROG
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CROSSREFS
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KEYWORD
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nonn,easy
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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