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 A135215 #5 Mar 31 2012 10:28:28
%S A135215 0,1,3,4,6,7,10,10,12,13,15
%N A135215 Maximal number of zero digits in square of number with n digits and without zero digits.
%t A135215 (*For a(7) *) mx = 0; Do[Do[Do[Do[Do[Do[Do[k = 10^6b + 10^5q + 10^4r + 10^3p + 10^2s + 10n + m; w = IntegerDigits[k^2]; ile = 0; Do[If[w[[t]] == 0, ile = ile + 1; If[ile > mx, mx = ile]], {t, 1, Length[w]}], {m, 1, 9}], {n, 1, 9}], {s, 1, 9}], {p, 1, 9}], {r, 1, 9}], {q, 1, 9}], {b, 1, 9}]; mx
%Y A135215 Cf. A134843, A134844, A134845, A134846, A134847, A134848, A134849.
%K A135215 nonn,base
%O A135215 1,3
%A A135215 _Artur Jasinski_, Nov 23 2007
%E A135215 a(8)-a(11) from _Lars Blomberg_, Jun 26 2011