a(n) = n*(2*n^2 + 5*n + 13)/2.

Terms

a(0) =0a(1) =10a(2) =31a(3) =69a(4) =130a(5) =220a(6) =345a(7) =511a(8) =724a(9) =990a(10) =1315a(11) =1705a(12) =2166a(13) =2704a(14) =3325a(15) =4035a(16) =4840a(17) =5746a(18) =6759a(19) =7885a(20) =9130a(21) =10500a(22) =12001a(23) =13639a(24) =15420a(25) =17350a(26) =19435a(27) =21681a(28) =24094a(29) =26680