a(n) = n*(6*n^2 - 8*n + 3).

Terms

a(0) =0a(1) =1a(2) =22a(3) =99a(4) =268a(5) =565a(6) =1026a(7) =1687a(8) =2584a(9) =3753a(10) =5230a(11) =7051a(12) =9252a(13) =11869a(14) =14938a(15) =18495a(16) =22576a(17) =27217a(18) =32454a(19) =38323a(20) =44860a(21) =52101a(22) =60082a(23) =68839a(24) =78408a(25) =88825a(26) =100126a(27) =112347a(28) =125524a(29) =139693