G.f. A(x) satisfies: A(x-x^2-x^3) = 1/sqrt(1-2*x-3*x^2), which is the g.f. the central trinomial coefficients (A002426).
A231373
G.f. A(x) satisfies: A(x-x^2-x^3) = 1/sqrt(1-2*x-3*x^2), which is the g.f. the central trinomial coefficients (A002426).
Terms
- a(0) =1a(1) =1a(2) =4a(3) =16a(4) =71a(5) =327a(6) =1550a(7) =7490a(8) =36720a(9) =182028a(10) =910330a(11) =4585318a(12) =23233722a(13) =118315318a(14) =605088690a(15) =3105994302a(16) =15994906965a(17) =82602799485a(18) =427662046960
External references
- oeis: A231373