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) |
|---|---|
| 2 | 0 |
| 3 | 1 |
| 4 | 126 |
| 5 | 13230 |
| 6 | 1580040 |
| 7 | 227026800 |
| 8 | 39502663200 |
| 9 | 8266953895200 |
| 10 | 2059096751712000 |
| 11 | 603711328396176000 |
| 12 | 206176565788633440000 |
| 13 | 81229359235705480800000 |
| 14 | 36597518579286942076800000 |
| 15 | 18708155260191426661632000000 |
| 16 | 10773738796571008900177536000000 |