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 | 2 |
| 4 | 26 |
| 5 | 274 |
| 6 | 2844 |
| 7 | 30708 |
| 8 | 351504 |
| 9 | 4292496 |
| 10 | 55988640 |
| 11 | 779171040 |
| 12 | 11545476480 |
| 13 | 181705299840 |
| 14 | 3029581820160 |
| 15 | 53376951801600 |
| 16 | 991337037465600 |
| 17 | 19363464423475200 |
| 18 | 396915849843609600 |
| 19 | 8520964324004966400 |
| 20 | 191220598650009600000 |
| 21 | 4477883953203763200000 |
| 22 | 109242544826541772800000 |