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 | 12870 |
| 3 | 9465511770 |
| 4 | 99561092450391000 |
| 5 | 151158246783053570131500 |
| 6 | 91756879673807945288868127380 |