2195580

Appears in sequences

• Sum of the path lengths of all binary trees with n edges.at n=10A138156
• Number of valleys at level 0 in all dispersed Dyck paths of length n (i.e., in all Motzkin paths of length n with no (1,0) steps at positive heights).at n=23A191389
• G.f. A(x,y) satisfies: A( x - y*A(x,y)^2, y) = x + (1-y)*A(x,y)^2, where the coefficients T(n,k) of x^n*y^k form a triangle read by rows n>=1, for k=0..n-1.at n=67A277295