a(n) = (5*n^2 - 3*n + 2)/2.

Terms

a(0) =1a(1) =2a(2) =8a(3) =19a(4) =35a(5) =56a(6) =82a(7) =113a(8) =149a(9) =190a(10) =236a(11) =287a(12) =343a(13) =404a(14) =470a(15) =541a(16) =617a(17) =698a(18) =784a(19) =875a(20) =971a(21) =1072a(22) =1178a(23) =1289a(24) =1405a(25) =1526a(26) =1652a(27) =1783a(28) =1919a(29) =2060