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 | 1 |
| 1 | 1 |
| 2 | 3 |
| 3 | 12 |
| 4 | 12 |
| 5 | 60 |
| 6 | 60 |
| 7 | 120 |
| 8 | 480 |
| 9 | 4320 |
| 10 | 43200 |
| 11 | 43200 |
| 12 | 518400 |
| 13 | 3628800 |
| 14 | 7257600 |
| 15 | 108864000 |
| 16 | 1741824000 |
| 17 | 1741824000 |
| 18 | 31352832000 |
| 19 | 31352832000 |
| 20 | 627056640000 |
| 21 | 13168189440000 |
| 22 | 289700167680000 |
| 23 | 289700167680000 |
| 24 | 6952804024320000 |
| 25 | 173820100608000000 |
| 26 | 4519322615808000000 |
| 27 | 122021710626816000000 |