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) |
|---|---|
| 1 | 1 |
| 2 | 2 |
| 3 | 8 |
| 4 | 32 |
| 5 | 128 |
| 6 | 864 |
| 7 | 3456 |
| 8 | 7776 |
| 9 | 31104 |
| 10 | 279936 |
| 11 | 497664 |
| 12 | 1990656 |
| 13 | 4478976 |
| 14 | 17915904 |
| 15 | 62208000 |
| 16 | 97200000 |
| 17 | 559872000 |
| 18 | 874800000 |
| 19 | 1555200000 |
| 20 | 6220800000 |
| 21 | 13996800000 |
| 22 | 55987200000 |