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 | 4 |
| 3 | 54 |
| 4 | 1720 |
| 5 | 97341 |
| 6 | 8360853 |
| 7 | 1001060834 |
| 8 | 155796077603 |
| 9 | 30055866217955 |