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 | 0 |
| 2 | 1 |
| 3 | 3 |
| 4 | 30 |
| 5 | 480 |
| 6 | 12000 |
| 7 | 430920 |
| 8 | 21052080 |
| 9 | 1343381760 |
| 10 | 108519626880 |
| 11 | 10825535952000 |
| 12 | 1307042125804800 |
| 13 | 187849403155814400 |
| 14 | 31691651643235584000 |
| 15 | 6201948133744691328000 |
| 16 | 1393497414722424211200000 |
| 17 | 356287752381703180566528000 |
| 18 | 102850159977463464656842752000 |