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 | 3 |
| 4 | 10 |
| 5 | 25 |
| 6 | 78 |
| 7 | 283 |
| 8 | 906 |
| 9 | 3044 |
| 10 | 10920 |
| 11 | 37920 |
| 12 | 135182 |
| 13 | 487555 |
| 14 | 1764216 |
| 15 | 6415902 |
| 16 | 23585285 |
| 17 | 86789112 |
| 18 | 320972293 |
| 19 | 1192327462 |
| 20 | 4441973622 |