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 A301872 #20 Jan 01 2019 20:16:47
%S A301872 0,1,2,9,10,25,66,188,568,1808,6024,20955,75816,284520,1104761,
%T A301872 4428896,18296575,77760442,339474192,1520281852,6975531533,
%U A301872 32755301642,157251442001,771100761895,3858854965090,19692136783074,102399111271982,542217184494641
%N A301872 Smallest integer k >= 0 such that the maximum digit of k^2 written in factorial base equals n.
%H A301872 Alois P. Heinz, <a href="/A301872/b301872.txt">Table of n, a(n) for n = 0..806</a>
%F A301872 a(n) = min { k >= 0 : max(A108731(k^2)) = n } = min { k >= 0 : A109381(k) = n }.
%e A301872 a(11) = 20955: A108731(20955^2) = [11,0,0,0,5,2,4,4,1,1,1].
%t A301872 Block[{nn = 10^5, r, s, t}, t = nn^2; r = Reverse@ Most@ NestWhileList[# + 1 &, 2, #! < t &]; s = Array[Max@ IntegerDigits[#^2, MixedRadix@ r] &, nn, 0]; Map[First@ FirstPosition[s, #] - 1 &, Union@ FoldList[Max, s]]] (* _Michael De Vlieger_, Jan 01 2019 *)
%Y A301872 Cf. A007623, A108731, A109381.
%K A301872 nonn,base
%O A301872 0,3
%A A301872 _Alois P. Heinz_, Mar 28 2018