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 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | 1 |
| 7 | 2 |
| 8 | 5 |
| 9 | 16 |
| 10 | 57 |
| 11 | 263 |
| 12 | 1532 |
| 13 | 10747 |
| 14 | 87948 |
| 15 | 803885 |
| 16 | 8020590 |
| 17 | 86027734 |
| 18 | 983417704 |
| 19 | 11913817317 |
| 20 | 152352034707 |
| 21 | 2050055948375 |
| 22 | 28951137255862 |
| 23 | 428085461764471 |