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 | 1 |
| 2 | 120 |
| 3 | 3654 |
| 4 | 45760 |
| 5 | 333375 |
| 6 | 1703016 |
| 7 | 6784540 |
| 8 | 22500864 |
| 9 | 64836045 |
| 10 | 167167000 |
| 11 | 393877506 |
| 12 | 861456960 |
| 13 | 1769830699 |
| 14 | 3447273480 |
| 15 | 6412923000 |
| 16 | 11461636096 |
| 17 | 19776716505 |
| 18 | 33076889784 |
| 19 | 53804808190 |
| 20 | 85365336000 |
| 21 | 132422893911 |
| 22 | 201268229800 |
| 23 | 300266132244 |
| 24 | 440396812800 |