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 | 17 |
| 4 | 129 |
| 5 | 2529 |
| 6 | 42753 |
| 7 | 1080561 |
| 8 | 28269825 |
| 9 | 910318785 |
| 10 | 31733067777 |
| 11 | 1260881785041 |
| 12 | 54451914027393 |
| 13 | 2588888715388065 |
| 14 | 132887134408562433 |
| 15 | 7371812870053439409 |
| 16 | 437841346658159352321 |
| 17 | 27782111830252836998529 |
| 18 | 1873198439610729939408897 |