a(n) = n^2 + a(n-1), with a(1)=0.

Terms

a(0) =0a(1) =4a(2) =13a(3) =29a(4) =54a(5) =90a(6) =139a(7) =203a(8) =284a(9) =384a(10) =505a(11) =649a(12) =818a(13) =1014a(14) =1239a(15) =1495a(16) =1784a(17) =2108a(18) =2469a(19) =2869a(20) =3310a(21) =3794a(22) =4323a(23) =4899a(24) =5524a(25) =6200a(26) =6929a(27) =7713a(28) =8554a(29) =9454