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 | 0 |
| 5 | 0 |
| 6 | 360 |
| 7 | 2520 |
| 8 | 48060 |
| 9 | 317520 |
| 10 | 4109040 |
| 11 | 12923136 |
| 12 | 238784940 |
| 13 | 559279980 |
| 14 | 7612394400 |
| 15 | 37864711260 |
| 16 | 246262998780 |
| 17 | 787758864480 |
| 18 | 13282478024760 |
| 19 | 27723264985920 |
| 20 | 387585094204260 |
| 21 | 1595144664454200 |