14707550

Appears in sequences

• Number T(n,k) of 2n-length strings of balanced parentheses of exactly k different types that are introduced in ascending order; triangle T(n,k), n>=0, 0<=k<=n, read by rows.at n=48A253180
• Number of 2n-length strings of balanced parentheses of exactly 3 different types that are introduced in ascending order.at n=6A258391