a(n) = Sum_{i=1..floor((n-1)/2)} i * (n-i)^2.

Terms

a(0) =0a(1) =0a(2) =4a(3) =9a(4) =34a(5) =57a(6) =134a(7) =196a(8) =370a(9) =500a(10) =830a(11) =1065a(12) =1624a(13) =2009a(14) =2884a(15) =3472a(16) =4764a(17) =5616a(18) =7440a(19) =8625a(20) =11110a(21) =12705a(22) =15994a(23) =18084a(24) =22334a(25) =25012a(26) =30394a(27) =33761a(28) =40460a(29) =44625