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 | 2 |
| 2 | 4 |
| 3 | 12 |
| 4 | 80 |
| 5 | 800 |
| 6 | 10752 |
| 7 | 181888 |
| 8 | 3714048 |
| 9 | 88915968 |
| 10 | 2442936320 |
| 11 | 75776712704 |
| 12 | 2619618852864 |
| 13 | 99879826948096 |
| 14 | 4163954627051520 |
| 15 | 188441538173337600 |
| 16 | 9200521811924615168 |
| 17 | 482067547423055544320 |
| 18 | 26980938272912248406016 |