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 | 5 |
| 2 | 45 |
| 3 | 450 |
| 4 | 4500 |
| 5 | 45000 |
| 6 | 450000 |
| 7 | 4500000 |
| 8 | 45000000 |
| 9 | 450000000 |
| 10 | 4500000000 |
| 11 | 45000000000 |
| 12 | 450000000000 |
| 13 | 4500000000000 |
| 14 | 45000000000000 |
| 15 | 450000000000000 |
| 16 | 4500000000000000 |
| 17 | 45000000000000000 |
| 18 | 450000000000000000 |
| 19 | 4500000000000000000 |
| 20 | 45000000000000000000 |
| 21 | 450000000000000000000 |