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) |
|---|---|
| 1 | 0 |
| 2 | 1 |
| 3 | 9 |
| 4 | 69 |
| 5 | 510 |
| 6 | 3738 |
| 7 | 27405 |
| 8 | 201569 |
| 9 | 1488762 |
| 10 | 11043318 |
| 11 | 82257890 |
| 12 | 615092178 |
| 13 | 4615882908 |
| 14 | 34752865332 |
| 15 | 262437282621 |
| 16 | 1987229885913 |