OFFSET
3,2
FORMULA
G.f.: z^3(1-z)^2M^5, with M the g.f. of the Motzkin numbers (A001006).
Conjecture: -(n+7)*(n-3)*a(n) +(4*n+17)*(n-3)*a(n-1) +(-2*n^2+13*n+27)*a(n-2) -(4*n+5)*(n-3)*a(n-3) +3*(n-3)*(n-4)*a(n-4)=0. - R. J. Mathar, Jun 23 2013
CROSSREFS
KEYWORD
nonn
AUTHOR
STATUS
approved