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.
| n | a(n) |
|---|---|
| 1 | 25 |
| 2 | 225 |
| 3 | 7225 |
| 4 | 27225 |
| 5 | 55225 |
| 6 | 2772225 |
| 7 | 227557225 |
| 8 | 277722225 |
| 9 | 27777222225 |
| 10 | 72272257225 |
| 11 | 2777772222225 |
| 12 | 25772527522225 |
| 13 | 277777722222225 |
| 14 | 2775552752755225 |
| 15 | 27522257555772225 |
| 16 | 27777777222222225 |
| 17 | 77525222275255225 |
| 18 | 257727727257277225 |
| 19 | 722555225555275225 |
| 20 | 2275752775775227225 |