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 | 4 |
| 2 | 72 |
| 3 | 96 |
| 4 | 21600 |
| 5 | 640 |
| 6 | 5080320 |
| 7 | 580608 |
| 8 | 326592000 |
| 9 | 20736000 |
| 10 | 2529128448 |
| 11 | 1094860800 |
| 12 | 1298164008960000 |
| 13 | 399435079680000 |
| 14 | 11298306539520000 |
| 15 | 231760134144000 |
| 16 | 48978158848819200000 |
| 17 | 768284844687360000 |
| 18 | 81541143706048266240000 |
| 19 | 1009797445276139520000 |
| 20 | 467359502609929273344000000 |