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 | 2 |
| 2 | 8 |
| 3 | 40 |
| 4 | 224 |
| 5 | 1328 |
| 6 | 8128 |
| 7 | 51664 |
| 8 | 344864 |
| 9 | 2419808 |
| 10 | 17690624 |
| 11 | 133255936 |
| 12 | 1025049088 |
| 13 | 8010533504 |
| 14 | 63486137600 |
| 15 | 510583994560 |
| 16 | 4173502486400 |
| 17 | 34713858911872 |
| 18 | 293845548560384 |
| 19 | 2528481737709056 |
| 20 | 22072195485742080 |
| 21 | 194999285532239872 |
| 22 | 1739475973516343296 |