n^2 + nextprime(n^2).

Terms

a(0) =3a(1) =9a(2) =20a(3) =33a(4) =54a(5) =73a(6) =102a(7) =131a(8) =164a(9) =201a(10) =248a(11) =293a(12) =342a(13) =393a(14) =452a(15) =513a(16) =582a(17) =655a(18) =728a(19) =801a(20) =884a(21) =971a(22) =1070a(23) =1153a(24) =1256a(25) =1353a(26) =1462a(27) =1571a(28) =1694a(29) =1807