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) |
|---|---|
| 3 | 1 |
| 4 | 9 |
| 5 | 56 |
| 6 | 301 |
| 7 | 1506 |
| 8 | 7258 |
| 9 | 34322 |
| 10 | 161039 |
| 11 | 755145 |
| 12 | 3556269 |
| 13 | 16876326 |
| 14 | 80881483 |
| 15 | 392014244 |
| 16 | 1922785012 |
| 17 | 9545380884 |
| 18 | 47947476888 |
| 19 | 243553779646 |
| 20 | 1250097073918 |
| 21 | 6477850149236 |
| 22 | 33857970839030 |
| 23 | 178339124650000 |
| 24 | 945852940569120 |