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 A036510 #14 Jul 27 2018 08:46:50
%S A036510 36,3136,343396,1336336,133333209,3333330225,313341333361,
%T A036510 1433333333961,43333334833636,1333333832344336,123133353336333376,
%U A036510 3233633330337433321,3333433332336331536,2333303333385023333376,133333533332333233936
%N A036510 Smallest square containing exactly n 3's.
%C A036510 a(20) > 10^28. - _Giovanni Resta_, Jul 27 2018
%H A036510 Giovanni Resta, <a href="/A036510/b036510.txt">Table of n, a(n) for n = 1..19</a> (first 17 terms from Jon E. Schoenfield)
%t A036510 a[n_] := Block[{k=1}, While[DigitCount[k^2, 10, 3] != n, k++]; k^2]; Array[a, 6] (* _Giovanni Resta_, Jul 27 2018 *)
%Y A036510 Cf. A048348. - _Jon E. Schoenfield_, Jan 24 2009
%K A036510 nonn,base
%O A036510 1,1
%A A036510 _David W. Wilson_
%E A036510 More terms from _Jon E. Schoenfield_, Jan 14 2009