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 | 2 |
| 4 | 7 |
| 5 | 36 |
| 6 | 182 |
| 7 | 1196 |
| 8 | 8699 |
| 9 | 76840 |
| 10 | 704834 |
| 11 | 7570716 |
| 12 | 84889638 |
| 13 | 1085246904 |
| 14 | 14322115212 |
| 15 | 211595659320 |
| 16 | 3216832016019 |
| 17 | 53984412657360 |
| 18 | 928559550102410 |
| 19 | 17440458896525180 |
| 20 | 334876925319944690 |
| 21 | 6960292943873805976 |
| 22 | 147563833511292247796 |
| 23 | 3362366089440205308072 |