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 A048350 #24 Mar 06 2025 10:47:57
%S A048350 5,75,235,745,22485,22925,235065,505525,2356384,23569166,227069495,
%T A048350 674919666,3931354166,7450205075,39969432765,524933839166,
%U A048350 2134374738666,4904646324166,23802428354166,159861050770834,725227930760773,1882963768916666,7586668936732745,74536940878685015,174801474694453186
%N A048350 a(n)^2 is the smallest square containing exactly n 5's.
%H A048350 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/SquareNumber.html">Square Number</a>
%t A048350 k := 1; For[n = 1, n < 30000, n++, If[DigitCount[n^2][[5]] == k, k++; Print[n]]] (* _Stefan Steinerberger_, Apr 09 2006 *)
%t A048350 a[n_] := Module[{i = 1}, While[DigitCount[i^2][[6]] != n, i++;]; i]; (* Sam Handler (sam_5_5_5_0(AT)yahoo.com), Aug 20 2006 *)
%Y A048350 Cf. A036512, A034986, A048351.
%K A048350 nonn,base
%O A048350 1,1
%A A048350 _Patrick De Geest_, Mar 15 1999
%E A048350 More terms from _Jon E. Schoenfield_, Jan 14 2009
%E A048350 One more term from _Jon E. Schoenfield_, Jan 25 2009
%E A048350 a(17)-a(19) from _Giovanni Resta_, Jul 27 2018
%E A048350 a(20)-a(25) from _Max Alekseyev_, Mar 06 2025