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 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 2 |
| 7 | 24 |
| 8 | 1705 |
| 9 | 8646064 |
| 10 | 120879712950776 |
| 11 | 6984325661199418257711189170 |
| 12 | 2037364946117781220616409939151494028465982215442078400 |