a(n) = (n!)^3 * Sum_{k=1..n-1} 1/(k*(n-k))^3.

A304589

a(n) = (n!)^3 * Sum_{k=1..n-1} 1/(k*(n-k))^3.

Terms

    a(0) =0a(1) =0a(2) =8a(3) =54a(4) =1240a(5) =70000a(6) =7941968a(7) =1589632128a(8) =512918521344

External references