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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 6 |
| 5 | 15 |
| 6 | 42 |
| 7 | 109 |
| 8 | 320 |
| 9 | 979 |
| 10 | 3137 |
| 11 | 10603 |
| 12 | 37728 |
| 13 | 140423 |
| 14 | 546859 |
| 15 | 2220294 |
| 16 | 9374309 |
| 17 | 41059926 |
| 18 | 186149869 |
| 19 | 871717073 |
| 20 | 4208841555 |
| 21 | 20917405824 |
| 22 | 106849492793 |