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 | 2 |
| 2 | 40 |
| 3 | 4680 |
| 4 | 1591200 |
| 5 | 1891936800 |
| 6 | 4270101357600 |
| 7 | 11089453225687200 |
| 8 | 32565776278494961756800 |
| 9 | 28429922691126101613686400 |
| 10 | 42204464874461454985621846571472000 |