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 | 1 |
| 2 | 4 |
| 3 | 8 |
| 4 | 88 |
| 5 | 252 |
| 6 | 2112 |
| 7 | 2112 |
| 8 | 2112 |
| 9 | 4224 |
| 10 | 8448 |
| 11 | 48384 |
| 12 | 48384 |
| 13 | 405504 |
| 14 | 405504 |
| 15 | 405504 |
| 16 | 40955904 |
| 17 | 677707776 |
| 18 | 677707776 |
| 19 | 677707776 |
| 20 | 677707776 |