a(n) = 13*n^2 + 7*n + 1.

Terms

a(0) =21a(1) =67a(2) =139a(3) =237a(4) =361a(5) =511a(6) =687a(7) =889a(8) =1117a(9) =1371a(10) =1651a(11) =1957a(12) =2289a(13) =2647a(14) =3031a(15) =3441a(16) =3877a(17) =4339a(18) =4827a(19) =5341a(20) =5881a(21) =6447a(22) =7039a(23) =7657a(24) =8301a(25) =8971a(26) =9667a(27) =10389a(28) =11137a(29) =11911