OFFSET
0,3
LINKS
G. C. Greubel, Table of n, a(n) for n = 0..1000
FORMULA
a(n) = Sum_{k=0..floor(n/2)} A116392(n-k,k).
D-finite with recurrence: n*a(n) +2*(-n+1)*a(n-1) +2*(-5*n+6)*a(n-2) +2*(3*n-7)*a(n-3) +2*(17*n-50)*a(n-4) +6*(5*n-17)*a(n-5) +9*(n-4)*a(n-6)=0. - R. J. Mathar, Jan 23 2020
MATHEMATICA
CoefficientList[Series[1/((1+x)*Sqrt[1-2x-3x^2] -x), {x, 0, 30}], x] (* G. C. Greubel, May 28 2019 *)
PROG
(PARI) my(x='x+O('x^30)); Vec(1/((1+x)*sqrt(1-2*x-3*x^2) - x)) \\ G. C. Greubel, May 28 2019
(Magma) R<x>:=PowerSeriesRing(Rationals(), 30); Coefficients(R!( 1/((1+x)*Sqrt(1-2*x-3*x^2) - x) )); // G. C. Greubel, May 28 2019
(Sage) (1/((1+x)*sqrt(1-2*x-3*x^2) - x)).series(x, 30).coefficients(x, sparse=False) # G. C. Greubel, May 28 2019
CROSSREFS
KEYWORD
easy,nonn
AUTHOR
Paul Barry, Feb 12 2006
STATUS
approved