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 | 0 |
| 2 | 0 |
| 3 | 84 |
| 4 | 210 |
| 5 | 3696 |
| 6 | 33264 |
| 7 | 392964 |
| 8 | 4879875 |
| 9 | 66106040 |
| 10 | 963266304 |
| 11 | 15032793048 |
| 12 | 250055167908 |
| 13 | 4415595820608 |
| 14 | 82483140014880 |
| 15 | 1624829831302104 |
| 16 | 33659674920420549 |
| 17 | 731455984834451184 |
| 18 | 16636624374027720832 |