a(n) = (n-2)*(14*n-39) for n > 2, otherwise a(n) = n.

Terms

a(0) =0a(1) =1a(2) =2a(3) =3a(4) =34a(5) =93a(6) =180a(7) =295a(8) =438a(9) =609a(10) =808a(11) =1035a(12) =1290a(13) =1573a(14) =1884a(15) =2223a(16) =2590a(17) =2985a(18) =3408a(19) =3859a(20) =4338a(21) =4845a(22) =5380a(23) =5943a(24) =6534a(25) =7153a(26) =7800a(27) =8475a(28) =9178a(29) =9909