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 | 93 |
| 3 | 8600 |
| 4 | 1719060 |
| 5 | 604727424 |
| 6 | 331079253120 |
| 7 | 260480095349760 |
| 8 | 278592031202284800 |
| 9 | 388855261570122547200 |
| 10 | 686533182382689959116800 |
| 11 | 1495779844806108697677004800 |
| 12 | 3942052104672989614027181260800 |
| 13 | 12360865524060039746012601384960000 |