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 | 16 |
| 5 | 1960 |
| 6 | 53744 |
| 7 | 692320 |
| 8 | 5599888 |
| 9 | 33001664 |
| 10 | 154215760 |
| 11 | 603563504 |
| 12 | 2052729728 |
| 13 | 6229649352 |
| 14 | 17202203680 |
| 15 | 43870041520 |
| 16 | 104531112928 |
| 17 | 234870173248 |
| 18 | 501360888160 |