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 A028819 #34 Feb 10 2025 20:00:06
%S A028819 0,1,2,3,4,5,6,7,12,13,15,16,17,34,35,37,38,67,83,106,107,116,117,167,
%T A028819 183,334,335,337,367,383,587,667,1633,1667,3334,3335,3337,3367,3383,
%U A028819 3667,4833,6667,16667,33334,33335,33337,33367,33667,36667,66667
%N A028819 Numbers whose square has its digits in nondecreasing order.
%C A028819 It appears that from a(53) onwards all terms have nondecreasing digits and has one of the following forms: 16..67, 3..34, 3..35, 3..37, 3..367, 3..36..67, 36..67 and 6..67 and all number of such forms are terms. - _Chai Wah Wu_, Dec 07 2015
%H A028819 Charles R Greathouse IV and Chai Wah Wu, <a href="/A028819/b028819.txt">Table of n, a(n) for n = 1..422</a> (n = 1..107 from Charles R Greathouse IV).
%H A028819 Patrick De Geest, <a href="https://www.worldofnumbers.com/nobase10pg2.htm">Palindromic Squares in bases 2 to 17</a>
%t A028819 okQ[n_]:=And@@(#[[2]]>=#[[1]]&/@Partition[IntegerDigits[n^2],2,1])
%t A028819 Select[Range[0,50000],okQ] (* _Harvey P. Dale_, Jan 09 2011 *)
%t A028819 Select[Range[0,10^5],LessEqual@@IntegerDigits[#^2]&] (* _Ray Chandler_, Jan 06 2014 *)
%o A028819 (PARI) mono(n)=n=eval(Vec(Str(n)));for(i=2,#n,if(n[i]<n[i-1],return(0)));1
%o A028819 for(n=1,1e5,if(mono(n^2),print1(n", "))) \\ _Charles R Greathouse IV_, Aug 22 2011
%o A028819 (Python)
%o A028819 from itertools import combinations_with_replacement
%o A028819 from gmpy2 import is_square, isqrt
%o A028819 A028819_list = [0] + [int(isqrt(n)) for n in (int(''.join(i)) for l in range(1,11) for i in combinations_with_replacement('123456789',l)) if is_square(n)] # _Chai Wah Wu_, Dec 07 2015
%Y A028819 Cf. A000290, A028820.
%K A028819 nonn,base
%O A028819 1,3
%A A028819 _Patrick De Geest_