OFFSET
2,1
LINKS
Vincenzo Librandi, Table of n, a(n) for n = 2..1000
Index entries for linear recurrences with constant coefficients, signature (1,3,-3,-3,3,1,-1)
FORMULA
G.f.: x^2*(12+3*x-13*x^2-2*x^3+4*x^4) / ((1+x)^3*(x-1)^4). - R. J. Mathar, Sep 25 2013
a(n) = 12*A058187(n-2) +3*A058187(n-3) -13*A058187(n-4) -2*A058187(n-5) +4*A058187(n-6). - R. J. Mathar, Sep 25 2013
From Colin Barker, Jan 29 2016: (Start)
a(n) = (4*n^3+3*((-1)^n+19)*n^2+2*(15*(-1)^n+61)*n+75*((-1)^n-1))/48.
a(n) = (2*n^3+30*n^2+76*n)/24 for n even.
a(n) = (2*n^3+27*n^2+46*n-75)/24 for n odd. (End)
MATHEMATICA
CoefficientList[Series[(12 + 3 x - 13 x^2 - 2 x^3 + 4 x^4)/((1 + x)^3 (x - 1)^4), {x, 0, 50}], x] (* Vincenzo Librandi, Sep 25 2013 *)
LinearRecurrence[{1, 3, -3, -3, 3, 1, -1}, {12, 15, 38, 45, 82, 94, 148}, 50] (* Harvey P. Dale, Jul 21 2015 *)
PROG
(PARI) Vec(x^2*(12+3*x-13*x^2-2*x^3+4*x^4)/((1+x)^3*(x-1)^4) + O(x^100)) \\ Colin Barker, Jan 29 2016
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
STATUS
approved