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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 1 |
| 4 | 3 |
| 5 | 13 |
| 6 | 64 |
| 7 | 470 |
| 8 | 4921 |
| 9 | 83997 |
| 10 | 2411453 |
| 11 | 123544541 |
| 12 | 11537642646 |
| 13 | 2013389528672 |