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 | 2 |
| 3 | 5 |
| 4 | 15 |
| 5 | 52 |
| 6 | 203 |
| 7 | 876 |
| 8 | 4115 |
| 9 | 20765 |
| 10 | 111301 |
| 11 | 627821 |
| 12 | 3698873 |
| 13 | 22623354 |
| 14 | 142940629 |
| 15 | 929208778 |
| 16 | 6194162081 |
| 17 | 42223649277 |
| 18 | 293640007995 |
| 19 | 2079196943605 |
| 20 | 14964254850197 |
| 21 | 109308213994757 |
| 22 | 809340696014733 |
| 23 | 6067405789245061 |
| 24 | 46008536947670701 |
| 25 | 352579939415882813 |