219918domain: NAppears in sequencesa(n) = Sum_{k <= n/2 } binomial(n-2k, 3k+1).at n=25A137357G.f. satisfies A(x) = 1 + x*A(x)*(1 + x^5*A(x)^3).at n=22A365733Expansion of 1/(1 - x^3/(1-x)^5).at n=16A369804a(n) = Sum_{k=0..floor((2*n+1)/3)} binomial(2*k+1,2*n-3*k+1).at n=18A391600