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 | 0 |
| 3 | 0 |
| 4 | 3 |
| 5 | 24 |
| 6 | 177 |
| 7 | 1347 |
| 8 | 10467 |
| 9 | 82029 |
| 10 | 644808 |
| 11 | 5073915 |
| 12 | 39939900 |
| 13 | 314427960 |
| 14 | 2475438408 |
| 15 | 19488960504 |
| 16 | 153435934587 |
| 17 | 1207997701872 |
| 18 | 9510543548457 |
| 19 | 74876345104299 |
| 20 | 589500202673403 |
| 21 | 4641125238026805 |
| 22 | 36539501601385200 |
| 23 | 287674887310843395 |
| 24 | 2264859596198883588 |