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 | 4 |
| 5 | 26 |
| 6 | 192 |
| 7 | 1551 |
| 8 | 13416 |
| 9 | 122770 |
| 10 | 1180496 |
| 11 | 11883079 |
| 12 | 124992672 |
| 13 | 1372811900 |
| 14 | 15741602608 |
| 15 | 188470662702 |
| 16 | 2356327731016 |
| 17 | 30760057620142 |
| 18 | 419124712458444 |
| 19 | 5956905826561685 |
| 20 | 88230307480324360 |
| 21 | 1360309585677285312 |