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 | 3 |
| 2 | 12 |
| 3 | 28 |
| 4 | 168 |
| 5 | 360 |
| 6 | 1170 |
| 7 | 9360 |
| 8 | 19344 |
| 9 | 232128 |
| 10 | 3249792 |
| 11 | 6604416 |
| 12 | 20321280 |
| 13 | 104993280 |
| 14 | 1889879040 |
| 15 | 37797580800 |
| 16 | 907141939200 |
| 17 | 1828682956800 |
| 18 | 54860488704000 |
| 19 | 1755535638528000 |
| 20 | 12508191424512000 |
| 21 | 37837279059148800 |
| 22 | 1437816604247654400 |
| 23 | 60388297378401484800 |