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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | 1400 |
| 7 | 16520 |
| 8 | 103040 |
| 9 | 455040 |
| 10 | 1602000 |
| 11 | 4840032 |
| 12 | 12815552 |
| 13 | 31069112 |
| 14 | 68954312 |
| 15 | 144449440 |
| 16 | 284461680 |
| 17 | 537258960 |
| 18 | 966579120 |