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 | 22 |
| 5 | 96 |
| 6 | 492 |
| 7 | 2952 |
| 8 | 20588 |
| 9 | 164990 |
| 10 | 1497740 |
| 11 | 15187692 |
| 12 | 169974040 |
| 13 | 2078905752 |
| 14 | 27567259896 |
| 15 | 393759207372 |
| 16 | 6025346314756 |
| 17 | 98317949671110 |
| 18 | 1703879074519500 |
| 19 | 31251488731748108 |
| 20 | 604748393942784976 |
| 21 | 12312387380060084768 |
| 22 | 263079571362773145632 |