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 | 4 |
| 2 | 60 |
| 3 | 2040 |
| 4 | 188080 |
| 5 | 74164384 |
| 6 | 140677401088 |
| 7 | 1132868741554944 |
| 8 | 36957109369822385664 |
| 9 | 4838033391155896811513344 |