Centered 12-gonal numbers, or centered dodecagonal numbers: numbers of the form 6*k*(k-1) + 1.

Terms

a(0) =1a(1) =13a(2) =37a(3) =73a(4) =121a(5) =181a(6) =253a(7) =337a(8) =433a(9) =541a(10) =661a(11) =793a(12) =937a(13) =1093a(14) =1261a(15) =1441a(16) =1633a(17) =1837a(18) =2053a(19) =2281a(20) =2521a(21) =2773a(22) =3037a(23) =3313a(24) =3601a(25) =3901a(26) =4213a(27) =4537a(28) =4873a(29) =5221