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 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 13 |
| 6 | 44 |
| 7 | 162 |
| 8 | 643 |
| 9 | 2724 |
| 10 | 12259 |
| 11 | 58423 |
| 12 | 293902 |
| 13 | 1555743 |
| 14 | 8640526 |
| 15 | 50222288 |
| 16 | 304792741 |
| 17 | 1927313470 |
| 18 | 12673784445 |
| 19 | 86517541197 |
| 20 | 612134881624 |
| 21 | 4482215342305 |
| 22 | 33919417267456 |
| 23 | 264951302794510 |
| 24 | 2133720505175351 |