Squares of odd hexagonal numbers.

Terms

a(0) =1a(1) =225a(2) =2025a(3) =8281a(4) =23409a(5) =53361a(6) =105625a(7) =189225a(8) =314721a(9) =494209a(10) =741321a(11) =1071225a(12) =1500625a(13) =2047761a(14) =2732409a(15) =3575881a(16) =4601025a(17) =5832225a(18) =7295401a(19) =9018009a(20) =11029041a(21) =13359025a(22) =16040025a(23) =19105641a(24) =22591009a(25) =26532801a(26) =30969225a(27) =35940025a(28) =41486481a(29) =47651409