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 | 25 |
| 5 | 135 |
| 6 | 913 |
| 7 | 7499 |
| 8 | 73191 |
| 9 | 833597 |
| 10 | 10917343 |
| 11 | 162402263 |
| 12 | 2715430931 |
| 13 | 50576761471 |
| 14 | 1041203832858 |
| 15 | 23529845888598 |