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 | 0 |
| 2 | 1 |
| 3 | 8 |
| 4 | 9 |
| 5 | 224 |
| 6 | 1225 |
| 7 | 11304 |
| 8 | 103537 |
| 9 | 1431296 |
| 10 | 15642801 |
| 11 | 206721800 |
| 12 | 3295533241 |
| 13 | 47467875168 |
| 14 | 859354139449 |
| 15 | 15596241280424 |
| 16 | 283240963555425 |
| 17 | 5859309797252864 |
| 18 | 129874369387025377 |
| 19 | 2752905169704533256 |
| 20 | 67640333903657850601 |