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 | 12 |
| 6 | 150 |
| 7 | 1200 |
| 8 | 7905 |
| 9 | 46400 |
| 10 | 255636 |
| 11 | 1346700 |
| 12 | 6901725 |
| 13 | 34663020 |
| 14 | 171786450 |
| 15 | 843130688 |
| 16 | 4110958530 |
| 17 | 19951305240 |
| 18 | 96528492700 |
| 19 | 466073976900 |
| 20 | 2247627076731 |
| 21 | 10832193571460 |
| 22 | 52194109216950 |