a(n) = n*(2*n - 3 - (-1)^n)*(11*n + (-1)^n)/24.

Terms

a(0) =0a(1) =0a(2) =16a(3) =30a(4) =90a(5) =134a(6) =266a(7) =356a(8) =588a(9) =740a(10) =1100a(11) =1330a(12) =1846a(13) =2170a(14) =2870a(15) =3304a(16) =4216a(17) =4776a(18) =5928a(19) =6630a(20) =8050a(21) =8910a(22) =10626a(23) =11660a(24) =13700a(25) =14924a(26) =17316a(27) =18746a(28) =21518a(29) =23170