a(n) = n^3 + n^2 + n + 1.

Terms

a(0) =1a(1) =4a(2) =15a(3) =40a(4) =85a(5) =156a(6) =259a(7) =400a(8) =585a(9) =820a(10) =1111a(11) =1464a(12) =1885a(13) =2380a(14) =2955a(15) =3616a(16) =4369a(17) =5220a(18) =6175a(19) =7240a(20) =8421a(21) =9724a(22) =11155a(23) =12720a(24) =14425a(25) =16276a(26) =18279a(27) =20440a(28) =22765a(29) =25260