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 | 4 |
| 3 | 30 |
| 4 | 321 |
| 5 | 4389 |
| 6 | 72512 |
| 7 | 1399755 |
| 8 | 30865353 |
| 9 | 764755508 |
| 10 | 21024535960 |
| 11 | 634924059276 |
| 12 | 20890221475598 |
| 13 | 743727414390456 |
| 14 | 28484480606420928 |
| 15 | 1167761832049224515 |
| 16 | 51022550712426870397 |
| 17 | 2366859765773183488674 |