209714

Appears in sequences

• A014486-encoding of plane binary trees (Stanley's d) whose interior zigzag-tree (Stanley's c, i.e., tree obtained by discarding the outermost edges of the binary tree) is isomorphic to a valid plane binary tree (Stanley's d).at n=9A080299
• G.f.: (4*x^2 + 2*x)/(4*x^3 - x^2 - 4*x + 1).at n=9A115243
• a(n) = floor(A140657(n+2)/10).at n=19A140659