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) |
|---|---|
| 2 | 1 |
| 3 | 2 |
| 4 | 30 |
| 5 | 568 |
| 6 | 69136 |
| 7 | 14222976 |
| 8 | 27406992000 |
| 9 | 90368686135296 |
| 10 | 3472530332565934080 |
| 11 | 231339455371699944947712 |
| 12 | 217930756388573091682145009664 |