Column 0 of triangle A107867; a(n) = C( n*(n-1)/2 + n + 1, n).

A107868

Column 0 of triangle A107867; a(n) = C( n*(n-1)/2 + n + 1, n).

Terms

    a(0) =1a(1) =2a(2) =6a(3) =35a(4) =330a(5) =4368a(6) =74613a(7) =1560780a(8) =38608020a(9) =1101716330a(10) =35607051480

External references