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 | 0 |
| 3 | 3 |
| 4 | 6 |
| 5 | 10 |
| 6 | 105 |
| 7 | 651 |
| 8 | 2968 |
| 9 | 18936 |
| 10 | 152505 |
| 11 | 1164295 |
| 12 | 9109056 |
| 13 | 80012868 |
| 14 | 756041377 |
| 15 | 7387199925 |
| 16 | 75535791360 |
| 17 | 816560002576 |
| 18 | 9254683835073 |
| 19 | 109135702334619 |
| 20 | 1338613513677280 |
| 21 | 17079079303721820 |
| 22 | 226148006163689841 |
| 23 | 3100114305453613393 |
| 24 | 43935964285680790368 |