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 | 12 |
| 3 | 1536 |
| 4 | 519045120 |
| 5 | 156130677884314787512320 |
| 6 | 12538151702000091464104493325082133822247601116646227522355200 |