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A066375
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a(n) = 6*binomial(n,4) + 3*binomial(n,3) + 4*binomial(n,2) - n + 2.
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2
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1, 4, 14, 40, 97, 206, 394, 694, 1145, 1792, 2686, 3884, 5449, 7450, 9962, 13066, 16849, 21404, 26830, 33232, 40721, 49414, 59434, 70910, 83977, 98776, 115454, 134164, 155065, 178322, 204106, 232594, 263969, 298420, 336142
(list;
graph;
refs;
listen;
history;
text;
internal format)
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OFFSET
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1,2
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LINKS
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FORMULA
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a(n) = (8 - 14*n + 13*n^2 - 4*n^3 + n^4)/4.
G.f.: x*(1 - x + 4*x^2 + 2*x^4)/(1-x)^5. (End)
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MATHEMATICA
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Table[6Binomial[n, 4]+3Binomial[n, 3]+4Binomial[n, 2]-n+2, {n, 40}] (* or *) LinearRecurrence[{5, -10, 10, -5, 1}, {1, 4, 14, 40, 97}, 40] (* Harvey P. Dale, Feb 05 2017 *)
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PROG
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(PARI) { for (n=1, 1000, a=6*binomial(n, 4) + 3*binomial(n, 3) + 4*binomial(n, 2) - n + 2; write("b066375.txt", n, " ", a) ) } \\ Harry J. Smith, Feb 11 2010
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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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STATUS
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approved
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