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 A379298 #23 Mar 29 2025 10:45:27
%S A379298 3,7,28,83,313,937,3114,9417,29614,94863,298327,987917,3162083,
%T A379298 9893887,29983327,99483667,315432874,994927133,2999833327,9486778167,
%U A379298 31464263856,99497231067,299998333327,999949483667,3160522105583,9892825177313,29999983333327
%N A379298 Largest number k for which k^2 is n digits long and has the maximum sum of digits possible for such a square (A371728(n)).
%F A379298 Conjecture: a(2*n) = A348303(n).
%e A379298 a(6) = 937 because among all 6-digit squares, 698896 = 836^2, 779689 = 883^2, 877969 = 937^2 have the maximum sum of digits 46 = A371728(6), and 937 is the largest.
%t A379298 a[n_] := Module[{s = Floor[Sqrt[(10^n - 1)]], max = 0},
%t A379298 For[k = s, k >= Ceiling[Sqrt[10^(n - 1)]], k--, t = DigitSum[k^2];
%t A379298 If[t > max, s = k; max = t]]; s];
%t A379298 Table[a[n], {n, 30}]
%Y A379298 Cf. A371728, A348303.
%Y A379298 Other powers: A380052, A380797, A380566, A380193.
%K A379298 nonn,base,more
%O A379298 1,1
%A A379298 _Zhining Yang_, Feb 05 2025