a(n) = 2*a(n-1) - a(n-2) + n + 1.

Terms

a(0) =1a(1) =2a(2) =6a(3) =14a(4) =27a(5) =46a(6) =72a(7) =106a(8) =149a(9) =202a(10) =266a(11) =342a(12) =431a(13) =534a(14) =652a(15) =786a(16) =937a(17) =1106a(18) =1294a(19) =1502a(20) =1731a(21) =1982a(22) =2256a(23) =2554a(24) =2877a(25) =3226a(26) =3602a(27) =4006a(28) =4439a(29) =4902