73645557469domain: NAppears in sequencesNumber of walks of length 2n+8 in the path graph P_9 from one end to the other.at n=17A005024Expansion of x^3/((1-3*x+x^2)*(1-5*x+5*x^2)).at n=21A094865Constant term of the reduction of the polynomial p(n,x)=(1/2)((x+2)^n+(x-2)^n) by x^2->x+1.at n=21A192353