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 | 1 |
| 2 | 720 |
| 3 | 51840 |
| 4 | 737280 |
| 5 | 9360000 |
| 6 | 37324800 |
| 7 | 276595200 |
| 8 | 754974720 |
| 9 | 3061100160 |
| 10 | 6739200000 |
| 11 | 25721308800 |
| 12 | 38220595200 |
| 13 | 137037962880 |
| 14 | 199148544000 |
| 15 | 485222400000 |
| 16 | 773094113280 |
| 17 | 2008994088960 |
| 18 | 2203992115200 |
| 19 | 6114035779200 |
| 20 | 6900940800000 |
| 21 | 14338695168000 |
| 22 | 18519342336000 |
| 23 | 41348052472320 |