Denominator of Sum_{k=1..n-1} 1/(k*(n-k))^2.

Terms

a(0) =1a(1) =1a(2) =1a(3) =2a(4) =144a(5) =72a(6) =64800a(7) =1800a(8) =2822400a(9) =3175200a(10) =317520000a(11) =635040a(12) =11064936960a(13) =15367968a(17) =259718659200