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 | 6 |
| 3 | 72 |
| 4 | 5184 |
| 5 | 4478976 |
| 6 | 278628139008 |
| 7 | 14975624970497949696 |
| 8 | 50071566192138943522512952098816 |
| 9 | 8998235963747242817865410245394871488270255869919232 |