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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 14 |
| 6 | 42 |
| 7 | 112 |
| 8 | 288 |
| 9 | 720 |
| 10 | 1760 |
| 11 | 4224 |
| 12 | 9984 |
| 13 | 23296 |
| 14 | 53760 |
| 15 | 122880 |
| 16 | 278528 |
| 17 | 626688 |
| 18 | 1400832 |
| 19 | 3112960 |
| 20 | 6881280 |
| 21 | 15138816 |
| 22 | 33161216 |
| 23 | 72351744 |
| 24 | 157286400 |
| 25 | 340787200 |
| 26 | 736100352 |
| 27 | 1585446912 |
| 28 | 3405774848 |
| 29 | 7298088960 |
| 30 | 15602810880 |
| 31 | 33285996544 |
| 32 | 70866960384 |