A135219 a(n) = largest number with n+1 digits and without zero digits whose squares have maximal number of zero digits = A135215(n+1).
99, 949, 9798, 62498, 997998, 6244998
Offset: 2
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.