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 | 9 |
| 3 | 212 |
| 4 | 9418 |
| 5 | 675014 |
| 6 | 71092502 |
| 7 | 10334690232 |
| 8 | 1982433606264 |
| 9 | 485065343565072 |
| 10 | 147433546709109408 |
| 11 | 54493722609862927632 |
| 12 | 24069397682825072219040 |
| 13 | 12520250948941157091235344 |
| 14 | 7575515622713954399390221008 |
| 15 | 5275250174853125498317783254528 |