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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 1 |
| 4 | 4 |
| 5 | 19 |
| 6 | 107 |
| 7 | 849 |
| 8 | 11100 |
| 9 | 261058 |
| 10 | 11716404 |
| 11 | 1006700026 |
| 12 | 164059811497 |
| 13 | 50335907479783 |
| 14 | 29003487412533265 |
| 15 | 31397381139819043520 |
| 16 | 63969560111526659139866 |
| 17 | 245871831681641239553413008 |
| 18 | 1787331725248249110678608976294 |
| 19 | 24636021429399437942454151113206764 |