Centered octachoral numbers.

Terms

a(0) =1a(1) =49a(2) =337a(3) =1249a(4) =3361a(5) =7441a(6) =14449a(7) =25537a(8) =42049a(9) =65521a(10) =97681a(11) =140449a(12) =195937a(13) =266449a(14) =354481a(15) =462721a(16) =594049a(17) =751537a(18) =938449a(19) =1158241a(20) =1414561a(21) =1711249a(22) =2052337a(23) =2442049a(24) =2884801a(25) =3385201a(26) =3948049a(27) =4578337a(28) =5281249a(29) =6062161