Let k=binomial(n-1,2); a(n) = n*(n-1)*k!/(k-n+1)! for n >= 4, with a(1)=a(2)=a(3)=0.

A119750

Let k=binomial(n-1,2); a(n) = n*(n-1)*k!/(k-n+1)! for n >= 4, with a(1)=a(2)=a(3)=0.

Terms

    a(0) =0a(1) =0a(2) =0a(3) =72a(4) =7200a(5) =907200a(6) =151351200a(7) =32818867200

External references