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 | 2 |
| 3 | 4 |
| 4 | 16 |
| 5 | 56 |
| 6 | 256 |
| 7 | 1072 |
| 8 | 6224 |
| 9 | 33616 |
| 10 | 218656 |
| 11 | 1326656 |
| 12 | 9893632 |
| 13 | 70186624 |
| 14 | 574017536 |
| 15 | 4454046976 |
| 16 | 40073925376 |
| 17 | 347165733632 |
| 18 | 3370414011904 |
| 19 | 31426411211776 |
| 20 | 328454079574016 |
| 21 | 3331595921852416 |
| 22 | 37125035407900672 |
| 23 | 400800185285464064 |
| 24 | 4744829049220673536 |