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 | 24 |
| 5 | 118 |
| 6 | 672 |
| 7 | 4255 |
| 8 | 29146 |
| 9 | 212028 |
| 10 | 1617344 |
| 11 | 12819065 |
| 12 | 104870276 |
| 13 | 881047470 |
| 14 | 7571873230 |
| 15 | 66363349857 |