a(n) = (12*n + 1)^2.

Terms

a(0) =1a(1) =169a(2) =625a(3) =1369a(4) =2401a(5) =3721a(6) =5329a(7) =7225a(8) =9409a(9) =11881a(10) =14641a(11) =17689a(12) =21025a(13) =24649a(14) =28561a(15) =32761a(16) =37249a(17) =42025a(18) =47089a(19) =52441a(20) =58081a(21) =64009a(22) =70225a(23) =76729a(24) =83521a(25) =90601a(26) =97969a(27) =105625a(28) =113569a(29) =121801