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 | 12 |
| 3 | 432 |
| 4 | 25920 |
| 5 | 2177280 |
| 6 | 235146240 |
| 7 | 31039303680 |
| 8 | 4842131374080 |
| 9 | 871583647334400 |
| 10 | 177803064056217600 |
| 11 | 40539098604817612800 |
| 12 | 10215852848414038425600 |
| 13 | 2819575386162274605465600 |
| 14 | 845872615848682381639680000 |
| 15 | 274062727534973091651256320000 |
| 16 | 95373829182170635894637199360000 |
| 17 | 35479064455767476552805038161920000 |