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 | 1 |
| 1 | 129 |
| 2 | 513 |
| 3 | 1665 |
| 4 | 5121 |
| 5 | 15489 |
| 6 | 46593 |
| 7 | 139905 |
| 8 | 419841 |
| 9 | 1259649 |
| 10 | 3779073 |
| 11 | 11337345 |
| 12 | 34012161 |
| 13 | 102036609 |
| 14 | 306109953 |
| 15 | 918329985 |
| 16 | 2754990081 |
| 17 | 8264970369 |
| 18 | 24794911233 |
| 19 | 74384733825 |
| 20 | 223154201601 |
| 21 | 669462604929 |
| 22 | 2008387814913 |
| 23 | 6025163444865 |
| 24 | 18075490334721 |
| 25 | 54226471004289 |