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 | 6 |
| 2 | 28 |
| 3 | 264 |
| 4 | 1104 |
| 5 | 3360 |
| 6 | 75840 |
| 7 | 6499584 |
| 8 | 151062912 |
| 9 | 2171581440 |
| 10 | 4686409728 |
| 11 | 316023611904 |