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 | 2 |
| 1 | 4 |
| 2 | 1 |
| 3 | 80 |
| 4 | 1 |
| 5 | 1120 |
| 6 | 1 |
| 7 | 44800 |
| 8 | 1 |
| 9 | 197120 |
| 10 | 1 |
| 11 | 1793792000 |
| 12 | 1 |
| 13 | 102502400 |
| 14 | 1 |
| 15 | 4879114240000 |
| 16 | 1 |
| 17 | 259568877568000 |
| 18 | 1 |
| 19 | 40789395046400000 |
| 20 | 1 |
| 21 | 238803367362560000 |
| 22 | 1 |
| 23 | 9561686829196902400000 |
| 24 | 1 |
| 25 | 1050734816395264000000 |
| 26 | 1 |
| 27 | 7922540515620290560000000 |
| 28 | 1 |
| 29 | 52951091790199773986816000000 |