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 | 7 |
| 4 | 37 |
| 5 | 201 |
| 6 | 1531 |
| 7 | 12433 |
| 8 | 112729 |
| 9 | 1158769 |
| 10 | 12920311 |
| 11 | 157007841 |
| 12 | 2063354437 |
| 13 | 29052921769 |
| 14 | 436908104179 |
| 15 | 6981843029281 |
| 16 | 118083965782321 |
| 17 | 2106973566128865 |
| 18 | 39538081855597807 |
| 19 | 778216030845226561 |
| 20 | 16027517577057849181 |
| 21 | 344635879922587951321 |