a(n) = n^3 - n^2.

Terms

a(0) =0a(1) =0a(2) =4a(3) =18a(4) =48a(5) =100a(6) =180a(7) =294a(8) =448a(9) =648a(10) =900a(11) =1210a(12) =1584a(13) =2028a(14) =2548a(15) =3150a(16) =3840a(17) =4624a(18) =5508a(19) =6498a(20) =7600a(21) =8820a(22) =10164a(23) =11638a(24) =13248a(25) =15000a(26) =16900a(27) =18954a(28) =21168a(29) =23548