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 | 2 |
| 2 | 5 |
| 3 | 16 |
| 4 | 65 |
| 5 | 286 |
| 6 | 1305 |
| 7 | 6232 |
| 8 | 30377 |
| 9 | 150178 |
| 10 | 750937 |
| 11 | 3785904 |
| 12 | 19215865 |
| 13 | 98086646 |
| 14 | 503087741 |
| 15 | 2591128000 |
| 16 | 13394476993 |
| 17 | 69466312210 |
| 18 | 361315132065 |
| 19 | 1884242109256 |
| 20 | 9849626540337 |
| 21 | 51599350440694 |
| 22 | 270851460356973 |