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 | 3 |
| 5 | 9 |
| 6 | 43 |
| 7 | 209 |
| 8 | 1042 |
| 9 | 5682 |
| 10 | 32875 |
| 11 | 200919 |
| 12 | 1299092 |
| 13 | 8848623 |
| 14 | 63108778 |
| 15 | 471509591 |
| 16 | 3671980053 |
| 17 | 29797471739 |
| 18 | 251120234182 |
| 19 | 2196428139810 |
| 20 | 19882638695048 |
| 21 | 186205573812059 |
| 22 | 1799766634300161 |
| 23 | 17946783669353462 |
| 24 | 184277407872729741 |
| 25 | 1947501874827169041 |