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 | 1 |
| 2 | 1 |
| 3 | 4 |
| 4 | 9 |
| 5 | 30 |
| 6 | 136 |
| 7 | 882 |
| 8 | 7626 |
| 9 | 84448 |
| 10 | 1159912 |
| 11 | 19226112 |
| 12 | 376464500 |
| 13 | 8556370952 |
| 14 | 222510227460 |
| 15 | 6542050923204 |
| 16 | 215278202878118 |
| 17 | 7860760142260830 |
| 18 | 316135809596510856 |