a(n) = (11*n^2 - 11*n + 2)/2.

Terms

a(0) =1a(1) =12a(2) =34a(3) =67a(4) =111a(5) =166a(6) =232a(7) =309a(8) =397a(9) =496a(10) =606a(11) =727a(12) =859a(13) =1002a(14) =1156a(15) =1321a(16) =1497a(17) =1684a(18) =1882a(19) =2091a(20) =2311a(21) =2542a(22) =2784a(23) =3037a(24) =3301a(25) =3576a(26) =3862a(27) =4159a(28) =4467a(29) =4786