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) |
|---|---|
| 2 | 1 |
| 3 | 7 |
| 4 | 32 |
| 5 | 160 |
| 6 | 832 |
| 7 | 4424 |
| 8 | 23872 |
| 9 | 130176 |
| 10 | 715520 |
| 11 | 3957448 |
| 12 | 21998176 |
| 13 | 122786976 |
| 14 | 687736896 |
| 15 | 3863423880 |
| 16 | 21758302848 |
| 17 | 122811081216 |
| 18 | 694533774336 |
| 19 | 3934558067336 |
| 20 | 22323615621280 |
| 21 | 126832567223712 |
| 22 | 721500116473664 |