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 | 2 |
| 3 | 6 |
| 4 | 24 |
| 5 | 104 |
| 6 | 528 |
| 7 | 3296 |
| 8 | 23168 |
| 9 | 179712 |
| 10 | 1573632 |
| 11 | 15207424 |
| 12 | 158880768 |
| 13 | 1801996288 |
| 14 | 22088716288 |
| 15 | 289379395584 |
| 16 | 4040899657728 |
| 17 | 60045059489792 |
| 18 | 944460646318080 |
| 19 | 15670973219667968 |
| 20 | 273813250221277184 |
| 21 | 5024207327266603008 |
| 22 | 96554813072964845568 |