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 | 1 |
| 3 | 4 |
| 4 | 16 |
| 5 | 90 |
| 6 | 562 |
| 7 | 3960 |
| 8 | 29311 |
| 9 | 225370 |
| 10 | 1766974 |
| 11 | 14030739 |
| 12 | 112269684 |
| 13 | 903020688 |