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 | 7 |
| 5 | 30 |
| 6 | 132 |
| 7 | 559 |
| 8 | 2416 |
| 9 | 10483 |
| 10 | 46072 |
| 11 | 204155 |
| 12 | 912779 |
| 13 | 4110644 |
| 14 | 18636572 |
| 15 | 84985825 |
| 16 | 389586145 |
| 17 | 1794268460 |
| 18 | 8298524480 |
| 19 | 38527095859 |
| 20 | 179487051589 |
| 21 | 838820171722 |
| 22 | 3931498431052 |
| 23 | 18475618863389 |
| 24 | 87036535974062 |
| 25 | 410947146076475 |