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 | 1 |
| 5 | 2 |
| 6 | 4 |
| 7 | 12 |
| 8 | 48 |
| 9 | 48 |
| 10 | 192 |
| 11 | 2880 |
| 12 | 2880 |
| 13 | 25920 |
| 14 | 552960 |
| 15 | 3265920 |
| 16 | 1935360 |
| 17 | 116121600 |
| 18 | 278691840 |
| 19 | 9405849600 |
| 20 | 26754416640 |
| 21 | 94058496000 |
| 22 | 3210529996800 |
| 23 | 869100503040000 |
| 24 | 423789959577600 |
| 25 | 927040536576000 |
| 26 | 135612787064832000 |