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 | 49 |
| 4 | 285 |
| 5 | 1717 |
| 6 | 10569 |
| 7 | 66013 |
| 8 | 416687 |
| 9 | 2651355 |
| 10 | 16976806 |
| 11 | 109256095 |
| 12 | 706071989 |
| 13 | 4579020513 |
| 14 | 29784426945 |
| 15 | 194231327451 |
| 16 | 1269457354069 |
| 17 | 8313189986612 |
| 18 | 54534379879411 |
| 19 | 358298017624625 |
| 20 | 2357331709694072 |
| 21 | 15528887031395023 |
| 22 | 102412421113465576 |
| 23 | 676104332189192702 |