a(n) = n^2*(n+1)*(n+2)!/48.

A037959

a(n) = n^2*(n+1)*(n+2)!/48.

Terms

    a(0) =6a(1) =90a(2) =1200a(3) =15750a(4) =211680a(5) =2963520a(6) =43545600a(7) =673596000a(8) =10977120000a(9) =188367379200

External references