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 | 3 |
| 4 | 24 |
| 5 | 199 |
| 6 | 1747 |
| 7 | 16474 |
| 8 | 168187 |
| 9 | 1859934 |
| 10 | 22228104 |
| 11 | 286078171 |
| 12 | 3949867548 |
| 13 | 58284826485 |
| 14 | 915905054360 |
| 15 | 15276520209206 |
| 16 | 269617872744249 |
| 17 | 5021159048900643 |
| 18 | 98417586560408168 |
| 19 | 2025488254833817394 |
| 20 | 43675043585825292775 |
| 21 | 984729344827900257489 |
| 22 | 23172929656443132617906 |