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 | 3 |
| 3 | 12 |
| 4 | 72 |
| 5 | 432 |
| 6 | 5184 |
| 7 | 41472 |
| 8 | 497664 |
| 9 | 5971968 |
| 10 | 107495424 |
| 11 | 1289945088 |
| 12 | 30958682112 |
| 13 | 433421549568 |
| 14 | 10402117189632 |
| 15 | 249650812551168 |
| 16 | 5991619501228032 |
| 17 | 107849151022104576 |
| 18 | 3882569436795764736 |