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) |
|---|---|
| 1 | 0 |
| 2 | 0 |
| 3 | 45 |
| 4 | 2304 |
| 5 | 34020 |
| 6 | 270720 |
| 7 | 1475145 |
| 8 | 6209280 |
| 9 | 21654864 |
| 10 | 65422080 |
| 11 | 176467005 |
| 12 | 434206080 |
| 13 | 990140580 |
| 14 | 2117816064 |
| 15 | 4288771305 |
| 16 | 8284308480 |
| 17 | 15355471680 |
| 18 | 27446584320 |
| 19 | 47501098029 |
| 20 | 79872376320 |
| 21 | 130866406020 |
| 22 | 209448328320 |
| 23 | 328150139625 |
| 24 | 504222960384 |
| 25 | 761083938000 |