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 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 120 |
| 6 | 720 |
| 7 | 5040 |
| 8 | 5032 |
| 9 | 4968 |
| 10 | 4320 |
| 11 | -2880 |
| 12 | -90000 |
| 13 | -1230480 |
| 14 | -17292240 |
| 15 | -17292225 |
| 16 | -17292000 |
| 17 | -17288160 |
| 18 | -17218800 |
| 19 | -15896880 |
| 20 | 10614960 |
| 21 | 568758960 |
| 22 | 568758938 |
| 23 | 568758454 |
| 24 | 568746816 |
| 25 | 568455360 |
| 26 | 560865360 |
| 27 | 355631760 |
| 28 | -5398802640 |
| 29 | -5398802611 |