a(0) = 0 and a(n) = (4*n^3 - 12*n^2 + 20*n - 9)/3 for n >= 1.

Terms

a(0) =0a(1) =1a(2) =5a(3) =17a(4) =45a(5) =97a(6) =181a(7) =305a(8) =477a(9) =705a(10) =997a(11) =1361a(12) =1805a(13) =2337a(14) =2965a(15) =3697a(16) =4541a(17) =5505a(18) =6597a(19) =7825a(20) =9197a(21) =10721a(22) =12405a(23) =14257a(24) =16285a(25) =18497a(26) =20901a(27) =23505a(28) =26317a(29) =29345