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) |
|---|---|
| 0 | 5 |
| 1 | 41 |
| 2 | 401 |
| 3 | 4001 |
| 4 | 40001 |
| 5 | 400001 |
| 6 | 4000001 |
| 7 | 40000001 |
| 8 | 400000001 |
| 9 | 4000000001 |
| 10 | 40000000001 |
| 11 | 400000000001 |
| 12 | 4000000000001 |
| 13 | 40000000000001 |
| 14 | 400000000000001 |
| 15 | 4000000000000001 |
| 16 | 40000000000000001 |
| 17 | 400000000000000001 |
| 18 | 4000000000000000001 |