a(n) = n*(n + 1)*(n^2 + n + 22)/24.

Terms

a(0) =0a(1) =2a(2) =7a(3) =17a(4) =35a(5) =65a(6) =112a(7) =182a(8) =282a(9) =420a(10) =605a(11) =847a(12) =1157a(13) =1547a(14) =2030a(15) =2620a(16) =3332a(17) =4182a(18) =5187a(19) =6365a(20) =7735a(21) =9317a(22) =11132a(23) =13202a(24) =15550a(25) =18200a(26) =21177a(27) =24507a(28) =28217a(29) =32335