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 | 1 |
| 2 | 4 |
| 3 | 20 |
| 4 | 113 |
| 5 | 682 |
| 6 | 4294 |
| 7 | 27830 |
| 8 | 184240 |
| 9 | 1239575 |
| 10 | 8446660 |
| 11 | 58150684 |
| 12 | 403735761 |