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 | 1 |
| 2 | 8 |
| 3 | 204 |
| 4 | 890 |
| 5 | 890 |
| 6 | 51311 |
| 7 | 286609 |
| 8 | 3580781 |
| 9 | 20875184 |
| 10 | 182289612 |
| 11 | 747240110 |
| 12 | 8656547082 |
| 13 | 8656547082 |
| 14 | 105545557489 |
| 15 | 783768630338 |
| 16 | 15026453160167 |
| 17 | 114725244868970 |
| 18 | 1045247300817798 |
| 19 | 9187315290370043 |
| 20 | 20586210475743186 |
| 21 | 20586210475743186 |