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A181343
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a(n) = (35*n^4 - 35*n^3 + 55*n^2 - 25*n + 6)/6.
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3
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6, 76, 386, 1251, 3126, 6606, 12426, 21461, 34726, 53376, 78706, 112151, 155286, 209826, 277626, 360681, 461126, 581236, 723426, 890251, 1084406, 1308726, 1566186, 1859901, 2193126, 2569256, 2991826, 3464511, 3991126, 4575626
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OFFSET
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1,1
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COMMENTS
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LINKS
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FORMULA
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a(n) = 4*a(n-1) - 6*a(n-2) + 4*a(n-3) - a(n-4) + 140 for n > 4; a(1)=6, a(2)=76, a(3)=386, a(4)=1251.
G.f.: x*(6 + 46*x + 66*x^2 + 21*x^3 + x^4)/(1-x)^5.
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MATHEMATICA
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LinearRecurrence[{5, -10, 10, -5, 1}, {6, 76, 386, 1251, 3126}, 30] (* Harvey P. Dale, Dec 06 2016 *)
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PROG
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(Magma) [ (35*n^4-35*n^3+55*n^2-25*n+6)/6: n in [1..30] ];
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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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