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 | 1 |
| 3 | 1 |
| 4 | 2 |
| 5 | 6 |
| 6 | 33 |
| 7 | 261 |
| 8 | 3125 |
| 9 | 54281 |
| 10 | 1360227 |
| 11 | 49213679 |
| 12 | 2551724168 |
| 13 | 189734190172 |
| 14 | 20202532257783 |
| 15 | 3077389342754387 |
| 16 | 670727373110373402 |
| 17 | 209089605110085626174 |
| 18 | 93228754516671937710239 |
| 19 | 59465333534426105454885059 |
| 20 | 54262238803939167296498684986 |