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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 31 |
| 6 | 143 |
| 7 | 1135 |
| 8 | 10287 |
| 9 | 155567 |
| 10 | 2789039 |
| 11 | 82439343 |
| 12 | 2938415279 |
| 13 | 171774189743 |
| 14 | 12207523172527 |
| 15 | 1419381685547183 |
| 16 | 201427441344229551 |
| 17 | 46711726513354322095 |
| 18 | 13247460522448782176431 |
| 19 | 6135846878080826487812271 |