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 | 3 |
| 2 | 14 |
| 3 | 82 |
| 4 | 568 |
| 5 | 4504 |
| 6 | 40016 |
| 7 | 392368 |
| 8 | 4198784 |
| 9 | 48616320 |
| 10 | 604921600 |
| 11 | 8043848960 |
| 12 | 113785080832 |
| 13 | 1705669278720 |
| 14 | 27007064393728 |
| 15 | 450422751508480 |
| 16 | 7893590619881472 |
| 17 | 145052304752934912 |
| 18 | 2789743827826573312 |
| 19 | 56063169473909817344 |