G.f. satisfies: A(x) = G(x)*A(x^2*G(x)) where G(x) is the g.f. of the Motzkin numbers (A001006): G = (1 + x*G + x^2*G^2).
A121399
G.f. satisfies: A(x) = G(x)*A(x^2*G(x)) where G(x) is the g.f. of the Motzkin numbers (A001006): G = (1 + x*G + x^2*G^2).
Terms
- a(0) =1a(1) =1a(2) =3a(3) =6a(4) =17a(5) =42a(6) =114a(7) =302a(8) =827a(9) =2263a(10) =6275a(11) =17468a(12) =48967a(13) =137834a(14) =389738a(15) =1105861a(16) =3148240a(17) =8987989a(18) =25726635a(19) =73808069a(20) =212196040a(21) =611219900a(22) =1763659860a(23) =5097131364a(24) =14752847173a(25) =42757853357a(26) =124080269331a(27) =360493591232
External references
- oeis: A121399