OFFSET
0,2
LINKS
Bruno Berselli, Table of n, a(n) for n = 0..1000
Index entries for linear recurrences with constant coefficients, signature (4,0,-2,-1).
FORMULA
G.f.: 1/((1-x)*(1-3*x-3*x^2-x^3)).
a(n) = 4*a(n-1)-2*a(n-3)-a(n-4).
MATHEMATICA
CoefficientList[Series[1/(1-4x+2x^3+x^4), {x, 0, 30}], x] (* or *) LinearRecurrence[{4, 0, -2, -1}, {1, 4, 16, 62}, 30] (* Harvey P. Dale, Dec 02 2011 *)
PROG
(PARI) Vec(1/(1-4*x+2*x^3+x^4)+O(x^25))
(Magma) m:=25; R<x>:=PowerSeriesRing(Integers(), m); Coefficients(R!(1/(1-4*x+2*x^3+x^4)));
(Maxima) makelist(coeff(taylor(1/(1-4*x+2*x^3+x^4), x, 0, n), x, n), n, 0, 24);
CROSSREFS
KEYWORD
nonn,easy
AUTHOR
Bruno Berselli, Sep 16 2011
STATUS
approved