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) |
|---|---|
| 4 | 0 |
| 5 | 8 |
| 6 | 90 |
| 7 | 1200 |
| 8 | 12502 |
| 9 | 111776 |
| 10 | 1017060 |
| 11 | 8762880 |
| 12 | 77887920 |
| 13 | 705522048 |
| 14 | 6268548000 |
| 15 | 60169824000 |
| 16 | 543692724960 |
| 17 | 5645713615360 |
| 18 | 52992483226560 |
| 19 | 596317674101760 |
| 20 | 5840267078534400 |
| 21 | 70071467744931840 |
| 22 | 725037082634304000 |
| 23 | 9448088175337574400 |
| 24 | 100728713738898432000 |