Appending a digit to n^2 gives another perfect square.

Terms

a(0) =1a(1) =2a(2) =4a(3) =5a(4) =6a(5) =12a(6) =18a(7) =43a(8) =80a(9) =154a(10) =191a(11) =228a(12) =456a(13) =684a(14) =1633a(15) =3038a(16) =5848a(17) =7253a(18) =8658a(19) =17316a(20) =25974a(21) =62011a(22) =115364a(23) =222070a(24) =275423a(25) =328776a(26) =657552a(27) =986328a(28) =2354785a(29) =4380794