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 A285550 #44 Jun 16 2025 11:35:42
%S A285550 0,1,2,3,7,10,12,20,21,30,38,70,97,100,102,107,120,138,200,201,210,
%T A285550 212,300,380,648,700,701,951,970,997,1000,1002,1007,1020,1049,1070,
%U A285550 1200,1380,1393,2000,2001,2010,2100,2120,3000,3148,3153,3451,3743,3747,3800,4462
%N A285550 Numbers k such that the digits of k^2 are squares.
%H A285550 Giovanni Resta, <a href="/A285550/b285550.txt">Table of n, a(n) for n = 1..10000</a> (first 350 terms from Colin Barker)
%F A285550 a(n) = sqrt(A019544(n)). - _Alois P. Heinz_, Apr 21 2017
%t A285550 Sqrt[#]&/@Select[Range[0,3800]^2,SubsetQ[{0,1,4,9},IntegerDigits[#]]&] (* _Harvey P. Dale_, Jun 14 2022 *)
%o A285550 (PARI) maxk=10000; L=List(); for(k=0, maxk, if(setminus(vecsort(digits(k^2),,8), [0,1,4,9]) == [], listput(L, k))); Vec(L)
%Y A285550 Cf. A000290, A019544, A046030.
%K A285550 nonn,base
%O A285550 1,3
%A A285550 _Colin Barker_, Apr 21 2017