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 | 2 |
| 3 | 5 |
| 4 | 66 |
| 5 | 7937 |
| 6 | 10211144 |
| 7 | 133506398361 |
| 8 | 18551599312980440 |
| 9 | 28652629505982770906471 |
| 10 | 510824181488832447063505273252 |