122657263474domain: NAppears in sequencesa(n) is the number of ways to evaluate a bivariate polynomial of the form p(T,X) = p00 + T * q(X) where q(X) is an univariate polynomial of degree n. Each addition or multiplication takes exactly two arguments, and two parenthesizations which are equal modulo commutativity are considered as a unique way to evaluate p(T,X).at n=5A173157