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 | 1 |
| 2 | 4 |
| 3 | 36 |
| 4 | 576 |
| 5 | 12800 |
| 6 | 360000 |
| 7 | 12192768 |
| 8 | 481890304 |
| 9 | 21743271936 |
| 10 | 1101996057600 |
| 11 | 61952000000000 |
| 12 | 3824628881965056 |
| 13 | 257164113195565056 |
| 14 | 18704075505689706496 |
| 15 | 1462975070062038220800 |
| 16 | 122444006400000000000000 |
| 17 | 10918111308394619734065152 |
| 18 | 1033255398127440061257744384 |