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) |
|---|---|
| 1 | 1 |
| 2 | 15 |
| 3 | 696 |
| 4 | 70380 |
| 5 | 13028148 |
| 6 | 3964560012 |
| 7 | 1842113636352 |
| 8 | 1238025608824896 |
| 9 | 1154488823507833920 |
| 10 | 1445382306218202517440 |
| 11 | 2365159362652507207703040 |
| 12 | 4947087474421921107685036800 |
| 13 | 12980259416603230936506795674880 |