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) |
|---|---|
| 0 | 1 |
| 1 | 5 |
| 2 | 45 |
| 3 | 630 |
| 4 | 12600 |
| 5 | 340200 |
| 6 | 11907000 |
| 7 | 523908000 |
| 8 | 28291032000 |
| 9 | 1838917080000 |
| 10 | 141596615160000 |
| 11 | 12743695364400000 |
| 12 | 1325344317897600000 |
| 13 | 157715973829814400000 |
| 14 | 21291656467024944000000 |