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 | 32 |
| 4 | 144 |
| 5 | 672 |
| 6 | 3200 |
| 7 | 15360 |
| 8 | 73984 |
| 9 | 356864 |
| 10 | 1722368 |
| 11 | 8314880 |
| 12 | 40144896 |
| 13 | 193830912 |
| 14 | 935886848 |
| 15 | 4518838272 |
| 16 | 21818834944 |
| 17 | 105350561792 |
| 18 | 508677324800 |
| 19 | 2456111022080 |
| 20 | 11859152338944 |
| 21 | 57261051346944 |
| 22 | 276480810549248 |