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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 3 |
| 5 | 3 |
| 6 | 9 |
| 7 | 13 |
| 8 | 52 |
| 9 | 140 |
| 10 | 501 |
| 11 | 1763 |
| 12 | 6785 |
| 13 | 25571 |
| 14 | 99907 |
| 15 | 392230 |
| 16 | 1564989 |
| 17 | 6297892 |
| 18 | 25601641 |
| 19 | 104846143 |
| 20 | 432629580 |