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 | 2 |
| 2 | 32 |
| 3 | 294 |
| 4 | 2304 |
| 5 | 16810 |
| 6 | 117600 |
| 7 | 799694 |
| 8 | 5326848 |
| 9 | 34928082 |
| 10 | 226195360 |
| 11 | 1450199542 |
| 12 | 9220780800 |
| 13 | 58221203066 |
| 14 | 365440965344 |
| 15 | 2282085037470 |
| 16 | 14187697422336 |
| 17 | 87860208024994 |
| 18 | 542209573735200 |
| 19 | 3335797263902918 |
| 20 | 20465738163774720 |
| 21 | 125247216613782858 |