265276342782domain: NAppears in sequencesa(n) = 2*det(M(n; -1))/det(M(n; 0)), where M(n; m) is the n X n matrix with (i,j)-th element equal to 1/binomial(n + i + j + m, n).at n=16A007226Number of ternary trees with n edges and such that the first leaf in the preorder traversal is at level 1.at n=16A121446