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 | 8 |
| 3 | 22 |
| 4 | 232 |
| 5 | 1016 |
| 6 | 12496 |
| 7 | 73648 |
| 8 | 1032032 |
| 9 | 7586272 |
| 10 | 118141696 |
| 11 | 1033672256 |
| 12 | 17668427008 |
| 13 | 178649596672 |
| 14 | 3313667912192 |
| 15 | 37898019913216 |
| 16 | 756948065453056 |
| 17 | 9640771045925888 |
| 18 | 205935949714235392 |
| 19 | 2885307792776353792 |
| 20 | 65568056040976818176 |