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 | 1 |
| 3 | 3 |
| 4 | 16 |
| 5 | 95 |
| 6 | 666 |
| 7 | 5327 |
| 8 | 47944 |
| 9 | 479439 |
| 10 | 5273830 |
| 11 | 63285959 |
| 12 | 822717468 |
| 13 | 11518044551 |
| 14 | 172770668266 |
| 15 | 2764330692255 |
| 16 | 46993621768336 |
| 17 | 845885191830047 |
| 18 | 16071818644770894 |
| 19 | 321436372895417879 |
| 20 | 6750163830803775460 |