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 A348303 #24 Nov 20 2021 11:36:01
%S A348303 7,83,937,9417,94863,987917,9893887,99483667,994927133,9486778167,
%T A348303 99497231067,999949483667,9892825177313
%N A348303 a(n) is the largest n-digit number whose square has a digital sum equal to A348300(n).
%t A348303 Array[#1 + Position[#2, Max[#2]][[-1, -1]] - 1 & @@ {#1, Map[Total@ IntegerDigits[#^2] &, Range[#1, #2]]} & @@ {10^(# - 1), 10^# - 1} &, 8] (* _Michael De Vlieger_, Oct 12 2021 *)
%Y A348303 Cf. A004159, A348300.
%K A348303 nonn,base,more
%O A348303 1,1
%A A348303 _Bernardo Recamán_ and _Freddy Barrera_, Oct 10 2021
%E A348303 a(11) from _Chai Wah Wu_, Nov 18 2021
%E A348303 a(12)-a(13) from _Martin Ehrenstein_, Nov 20 2021