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) |
|---|---|
| 6 | 1 |
| 7 | 30 |
| 8 | 560 |
| 9 | 9440 |
| 10 | 156592 |
| 11 | 2613664 |
| 12 | 44169600 |
| 13 | 756712960 |
| 14 | 13136471040 |
| 15 | 230851792896 |
| 16 | 4102116843520 |
| 17 | 73626174750720 |
| 18 | 1333446495436800 |
| 19 | 24347500823838720 |
| 20 | 447847464256929792 |
| 21 | 8292879605769961472 |
| 22 | 154496591977544417280 |
| 23 | 2894283145228079595520 |
| 24 | 54496565896255729827840 |
| 25 | 1030917988055843180904448 |