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) |
|---|---|
| 0 | 1 |
| 1 | 12 |
| 2 | 72 |
| 3 | 312 |
| 4 | 1152 |
| 5 | 3912 |
| 6 | 12672 |
| 7 | 39912 |
| 8 | 123552 |
| 9 | 378312 |
| 10 | 1150272 |
| 11 | 3481512 |
| 12 | 10505952 |
| 13 | 31640712 |
| 14 | 95167872 |
| 15 | 285995112 |
| 16 | 858968352 |
| 17 | 2578871112 |
| 18 | 7740545472 |
| 19 | 23229500712 |
| 20 | 69704230752 |
| 21 | 209144149512 |
| 22 | 627495363072 |
| 23 | 1882611918312 |
| 24 | 5648087413152 |
| 25 | 16944765555912 |
| 26 | 50835303300672 |