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 | 1 |
| 3 | 1 |
| 4 | 4 |
| 5 | 4 |
| 6 | 48 |
| 7 | 48 |
| 8 | 192 |
| 9 | 1728 |
| 10 | 34560 |
| 11 | 34560 |
| 12 | 414720 |
| 13 | 414720 |
| 14 | 2903040 |
| 15 | 130636800 |
| 16 | 2090188800 |
| 17 | 2090188800 |
| 18 | 25082265600 |
| 19 | 25082265600 |
| 20 | 501645312000 |
| 21 | 31603654656000 |
| 22 | 347640201216000 |
| 23 | 347640201216000 |
| 24 | 5562243219456000 |
| 25 | 139056080486400000 |