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 | 2 |
| 3 | 47 |
| 4 | 3537 |
| 5 | 990504 |
| 6 | 1052216730 |
| 7 | 4368243719790 |
| 8 | 71899754628285990 |
| 9 | 4719127231162959826680 |
| 10 | 1237680394434222243386835240 |
| 11 | 1297992518900121521819851167607200 |