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 | 0 |
| 5 | 0 |
| 6 | 0 |
| 7 | 504 |
| 8 | 32256 |
| 9 | 1460592 |
| 10 | 59814720 |
| 11 | 2403157680 |
| 12 | 98055619200 |
| 13 | 4129943329512 |
| 14 | 180976836968928 |
| 15 | 8281570545448200 |
| 16 | 396324506640142080 |
| 17 | 19840151844921504096 |
| 18 | 1038497761573246945152 |
| 19 | 56790713866712335971552 |
| 20 | 3241264004352759793685760 |