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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 21 |
| 4 | 335 |
| 5 | 5000 |
| 6 | 74524 |
| 7 | 1139292 |
| 8 | 18083484 |
| 9 | 299705400 |
| 10 | 5198985576 |
| 11 | 94461323616 |
| 12 | 1797180658272 |
| 13 | 35776357096896 |
| 14 | 744402741205824 |
| 15 | 16169795109262080 |
| 16 | 366214212167489280 |
| 17 | 8636605663418933760 |