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 | 1 |
| 3 | 3 |
| 4 | 7 |
| 5 | 23 |
| 6 | 84 |
| 7 | 364 |
| 8 | 1792 |
| 9 | 9953 |
| 10 | 61455 |
| 11 | 417720 |
| 12 | 3098515 |
| 13 | 24902930 |
| 14 | 215538825 |
| 15 | 1998518430 |
| 16 | 19761943208 |
| 17 | 207571259703 |
| 18 | 2307812703419 |
| 19 | 27075591512866 |
| 20 | 334263981931669 |