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 | 8 |
| 4 | 59 |
| 5 | 420 |
| 6 | 2940 |
| 7 | 20384 |
| 8 | 140479 |
| 9 | 964184 |
| 10 | 6598481 |
| 11 | 45059872 |
| 12 | 307197620 |
| 13 | 2091615760 |
| 14 | 14226362200 |
| 15 | 96680047568 |
| 16 | 656559634503 |
| 17 | 4456100344560 |
| 18 | 30228597199443 |
| 19 | 204971912361512 |
| 20 | 1389342336011059 |
| 21 | 9414200925647540 |
| 22 | 63772600432265968 |
| 23 | 431892497914345472 |