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 | 3 |
| 2 | 1944 |
| 3 | 4102777008 |
| 4 | 140890630179993255936 |
| 5 | 247470977313135626800897828778803200 |
| 6 | 54132901224855040835735917614114353691165557521593139200 |