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 | 21 |
| 3 | 1849 |
| 4 | 426405 |
| 5 | 203374081 |
| 6 | 173959321557 |
| 7 | 242527666641289 |
| 8 | 514557294036701349 |
| 9 | 1577689559404884503761 |
| 10 | 6714435826042791310638741 |
| 11 | 38401291553086405072860452569 |
| 12 | 287412720357301174793668207559205 |
| 13 | 2753382861926383584939774967275568801 |