G.f. A(x) satisfies: A(x) = 1 + x*A(x)/(1 - 2*x*A(x) - x^2*A(x)^2).

A307412

G.f. A(x) satisfies: A(x) = 1 + x*A(x)/(1 - 2*x*A(x) - x^2*A(x)^2).

Terms

    a(0) =1a(1) =1a(2) =3a(3) =12a(4) =53a(5) =250a(6) =1234a(7) =6295a(8) =32925a(9) =175616a(10) =951596a(11) =5223658a(12) =28987546a(13) =162349759a(14) =916502869a(15) =5209630108a(16) =29792226533a(17) =171284524184a(18) =989460348216

External references