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 | 0 |
| 1 | 0 |
| 2 | 1 |
| 3 | 2 |
| 4 | 7 |
| 5 | 26 |
| 6 | 117 |
| 7 | 594 |
| 8 | 3407 |
| 9 | 21682 |
| 10 | 151853 |
| 11 | 1160026 |
| 12 | 9600567 |
| 13 | 85566378 |
| 14 | 817099909 |
| 15 | 8322907298 |
| 16 | 90074979487 |
| 17 | 1032183177314 |
| 18 | 12485056392285 |
| 19 | 158964674218410 |
| 20 | 2125201153260167 |
| 21 | 29764791617545690 |
| 22 | 435823661971532981 |
| 23 | 6658895050949717362 |
| 24 | 105979606291488794607 |