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 A045540 #16 Aug 11 2024 14:41:31
%S A045540 1,2,3,4,5,6,7,8,9,13,14,16,17,18,19,23,24,25,27,28,29,31,32,33,36,37,
%T A045540 42,43,44,48,49,51,52,53,54,55,57,59,61,64,66,69,71,72,73,74,78,79,82,
%U A045540 84,86,87,88,89,93,95,96,98,99,113,116,117,118,124,126,128,133,134,136
%N A045540 Numbers whose square contains an equal number of each digit that it contains.
%C A045540 The sequence is expected to be infinite. Heuristically, if m is divisible by 10 there should be approximately constant * 10^(m/2)/m^(9/2) m-digit squares where all 10 digits have frequency m/10. - _Robert Israel_, Aug 14 2015
%H A045540 Robert Israel, <a href="/A045540/b045540.txt">Table of n, a(n) for n = 1..3000</a>
%H A045540 P. De Geest, <a href="https://www.worldofnumbers.com/samedigits.htm">Numbers whose digits occur with same frequency</a>
%p A045540 filter:= proc(n) local x,i,P;
%p A045540 P:= add(x^i, i=convert(n^2,base,10));
%p A045540 nops({coeffs(P,x)}) = 1
%p A045540 end proc:
%p A045540 select(filter, [$1..10^4]); # _Robert Israel_, Aug 14 2015
%t A045540 t={}; Do[If[Length[DeleteDuplicates[Transpose[Tally[IntegerDigits[n^2]]][[2]]]]==1,AppendTo[t,n]],{n,136}]; t (* _Jayanta Basu_, May 10 2013 *)
%Y A045540 Cf. A052046, A052047, A052048, A052049, A052050, A052051, A052052, A052060.
%K A045540 base,nonn
%O A045540 1,2
%A A045540 _Erich Friedman_