A032768 - OEIS

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A032768

a(n) = floor( n(n+1)(n+2)(n+3)(n+4) / (n+(n+1)+(n+2)+(n+3)+(n+4)) ).

0, 8, 36, 100, 224, 432, 756, 1232, 1900, 2808, 4004, 5544, 7488, 9900, 12852, 16416, 20672, 25704, 31600, 38456, 46368, 55440, 65780, 77500, 90720, 105560, 122148, 140616, 161100, 183744, 208692, 236096, 266112, 298900, 334628, 373464, 415584

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,2

LINKS

Vincenzo Librandi, Table of n, a(n) for n = 0..1000

Index entries for linear recurrences with constant coefficients, signature (4,-6,4,-1,1,-4,6,-4,1).

FORMULA

G.f.: 4*x*(1+x)*(2-x+2*x^2)/((1-x)^5*(1+x+x^2+x^3+x^4)).

a(n) = floor( n(n+1)(n+3)(n+4)/5 ). [Bruno Berselli, Jun 20 2012]

MATHEMATICA

CoefficientList[Series[4*x*(1+x)*(2-x+2*x^2)/((1-x)^5*(1+x+x^2+x^3+x^4)), {x, 0, 40}], x] (* Vincenzo Librandi, Jun 20 2012 *)

PROG