a(n) = Sum_{k=0..floor(n/2)} (n-k)^2.

Terms

a(0) =0a(1) =1a(2) =5a(3) =13a(4) =29a(5) =50a(6) =86a(7) =126a(8) =190a(9) =255a(10) =355a(11) =451a(12) =595a(13) =728a(14) =924a(15) =1100a(16) =1356a(17) =1581a(18) =1905a(19) =2185a(20) =2585a(21) =2926a(22) =3410a(23) =3818a(24) =4394a(25) =4875a(26) =5551a(27) =6111a(28) =6895a(29) =7540