This is a front-end for the Online Encyclopedia of Integer Sequences, made by Christian Perfect. The idea is to provide OEIS entries in non-ancient HTML, and then to think about how they're presented visually. The source code is on GitHub.
%I A031151 #26 Oct 18 2024 16:29:38
%S A031151 1,25,121,225,1225,1521,55225,112225,212521,511225,1525225,2512225,
%T A031151 5112121,5221225,11122225,152152225,1111222225,1155252121,1222551225,
%U A031151 5225121225,15211522225,111112222225,1212225222121,1521115222225,11111122222225,122212251151225,152111152222225
%N A031151 Squares composed of digits {1,2,5}.
%C A031151 Includes all numbers of the form ((10^k-1)/3 + 2)^2 for k >= 1, of the form (37*(10^k - 1)/3 + 14)^2 for k >= 2, and of the form ((10^k - 1)/3 + 171152)^2 for k >= 10. - _Andrew Howroyd_, Oct 18 2024
%H A031151 Zhao Hui Du, <a href="/A031151/b031151.txt">Table of n, a(n) for n = 1..113</a>
%H A031151 Patrick De Geest, <a href="http://www.worldofnumbers.com/threedigits.htm">Squares containing at most three distinct digits, Index entries for related sequences</a>
%F A031151 a(n) = A031153(n)^2. - _Andrew Howroyd_, Oct 18 2024
%t A031151 Select[Range[0,10^6]^2, SubsetQ[{1,2,5}, DeleteDuplicates[IntegerDigits[#]]]&] (* _Stefano Spezia_, Mar 09 2024 *)
%Y A031151 Cf. A031153.
%K A031151 nonn,base
%O A031151 1,2
%A A031151 _Patrick De Geest_
%E A031151 a(24)-a(27) from _Stefano Spezia_, Mar 09 2024