OFFSET
1,3
FORMULA
G.f.: (1+x+x^2-sqrt(1-2*x-x^2-10*x^3+x^4))/2. - Vladeta Jovovic, May 07 2003
Conjecture: n*a(n) +(-2*n+3)*a(n-1) +(-n+3)*a(n-2) +5*(-2*n+9)*a(n-3) +(n-6)*a(n-4)=0. - R. J. Mathar, Feb 25 2015
MATHEMATICA
CoefficientList[Series[(1+x+x^2-Sqrt[(1-2x-x^2-10x^3+x^4)])/2, {x, 0, 40}], x] (* Harvey P. Dale, Aug 31 2020 *)
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved