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 | 1 |
| 2 | 6 |
| 3 | 36 |
| 4 | 336 |
| 5 | 3720 |
| 6 | 50400 |
| 7 | 791280 |
| 8 | 14232960 |
| 9 | 287763840 |
| 10 | 6466521600 |
| 11 | 159826867200 |
| 12 | 4309577395200 |
| 13 | 125885452492800 |
| 14 | 3960073877760000 |
| 15 | 133473015067392000 |
| 16 | 4798579092443136000 |
| 17 | 183299247820136448000 |