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 | 1 |
| 3 | 1 |
| 4 | 1 |
| 5 | 1 |
| 6 | 1 |
| 7 | 1 |
| 8 | 1 |
| 9 | 90720 |
| 10 | 1 |
| 11 | 1 |
| 12 | 1 |
| 13 | 14968800 |
| 14 | 40864824000 |
| 15 | 1 |
| 16 | 1 |
| 17 | 453600 |
| 18 | 5108114880 |
| 19 | 131993382447360 |
| 20 | 3463115239584000000 |