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 | 1 |
| 1 | 1 |
| 2 | 1 |
| 3 | 3 |
| 4 | 15 |
| 5 | 35 |
| 6 | 225 |
| 7 | 1197 |
| 8 | 6881 |
| 9 | 45369 |
| 10 | 327375 |
| 11 | 2460755 |
| 12 | 19925367 |
| 13 | 171368067 |
| 14 | 1551364997 |
| 15 | 14763620445 |
| 16 | 147405166785 |
| 17 | 1538113071857 |
| 18 | 16732908859599 |
| 19 | 189413984297187 |
| 20 | 2226589748578775 |
| 21 | 27130592749003275 |
| 22 | 342118450334269917 |
| 23 | 4458168165784234253 |
| 24 | 59952936723606219009 |