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A054778
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5n*(5n-1)*(5n-2)*(5n-3)*(5n-4).
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0
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0, 120, 30240, 360360, 1860480, 6375600, 17100720, 38955840, 78960960, 146611080, 254251200, 417451320, 655381440, 991186560, 1452361680, 2071126800, 2884801920, 3936182040, 5273912160, 6952862280, 9034502400, 11587277520, 14686982640, 18417137760
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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) = A052787(5n) = 120*binomial(5*n, 5).
a(n) = 6*a(n-1)-15*a(n-2)+20*a(n-3)-15*a(n-4)+6*a(n-5)-a(n-6), with a(0)=0, a(1)=120, a(2)=30240, a(3)=360360, a(4)=1860480, a(5)=6375600. - Harvey P. Dale, Aug 29 2012
G.f.: 120*x*(126*x^4+1246*x^3+1506*x^2+246*x+1) / (x-1)^6. - Colin Barker, Sep 13 2014
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MATHEMATICA
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With[{f=Times@@(5n-Range[0, 4])}, Table[f, {n, 0, 30}]] (* or *) LinearRecurrence[ {6, -15, 20, -15, 6, -1}, {0, 120, 30240, 360360, 1860480, 6375600}, 30] (* Harvey P. Dale, Aug 29 2012 *)
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PROG
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(PARI) concat(0, Vec(120*x*(126*x^4+1246*x^3+1506*x^2+246*x+1)/(x-1)^6 + O(x^100))) \\ Colin Barker, Sep 13 2014
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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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