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 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 4 |
| 6 | 8 |
| 7 | 24 |
| 8 | 72 |
| 9 | 216 |
| 10 | 864 |
| 11 | 3456 |
| 12 | 13824 |
| 13 | 69120 |
| 14 | 345600 |
| 15 | 1728000 |
| 16 | 10368000 |
| 17 | 62208000 |
| 18 | 373248000 |
| 19 | 2612736000 |
| 20 | 18289152000 |
| 21 | 128024064000 |
| 22 | 1024192512000 |
| 23 | 8193540096000 |
| 24 | 65548320768000 |
| 25 | 589934886912000 |
| 26 | 5309413982208000 |
| 27 | 47784725839872000 |