Squares composed of digits {1,2,5}.

Terms

a(0) =1a(1) =25a(2) =121a(3) =225a(4) =1225a(5) =1521a(6) =55225a(7) =112225a(8) =212521a(9) =511225a(10) =1525225a(11) =2512225a(12) =5112121a(13) =5221225a(14) =11122225a(15) =152152225a(16) =1111222225a(17) =1155252121a(18) =1222551225a(19) =5225121225a(20) =15211522225a(21) =111112222225