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 | 1 |
| 2 | 3 |
| 3 | 20 |
| 4 | 272 |
| 5 | 7424 |
| 6 | 405504 |
| 7 | 44302336 |
| 8 | 9680453632 |
| 9 | 4230542786560 |
| 10 | 3697657604210688 |
| 11 | 6463791365183504384 |
| 12 | 22598414411798807576576 |
| 13 | 158015104883301198495481856 |
| 14 | 2209780998563745292895322636288 |