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 | 9 |
| 3 | 79 |
| 4 | 898 |
| 5 | 11370 |
| 6 | 153148 |
| 7 | 2150836 |
| 8 | 31140511 |
| 9 | 461462144 |
| 10 | 6964815000 |
| 11 | 106691488130 |
| 12 | 1654539334220 |
| 13 | 25923944408960 |
| 14 | 409770113121064 |
| 15 | 6526344613981944 |
| 16 | 104632592920840659 |
| 17 | 1687270854882480906 |
| 18 | 27348675382672733281 |
| 19 | 445328790513987869681 |
| 20 | 7281393330439106226281 |