Number of terms in the expansion of Product(x_i + x_{i+1} + ... + x_j) over 1 <= i < j <= n.

A087422

Number of terms in the expansion of Product(x_i + x_{i+1} + ... + x_j) over 1 <= i < j <= n.

Terms

    a(0) =1a(1) =1a(2) =2a(3) =8a(4) =55a(5) =567a(6) =7958a(7) =142396a(8) =3104160a(9) =79813513

External references