Expansion of (1+x*C)*C^3, where C = (1-sqrt(1-4*x))/(2*x) is g.f. for Catalan numbers, A000108.

A070031

Expansion of (1+x*C)*C^3, where C = (1-sqrt(1-4*x))/(2*x) is g.f. for Catalan numbers, A000108.

Terms

    a(0) =1a(1) =4a(2) =13a(3) =42a(4) =138a(5) =462a(6) =1573a(7) =5434a(8) =19006a(9) =67184a(10) =239666a(11) =861764a(12) =3120180a(13) =11366370a(14) =41630805a(15) =153216570a(16) =566343030a(17) =2101610280a(18) =7826451270a(19) =29240172780a(20) =109566326220a(21) =411671536380

External references