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 | 135 |
| 2 | 11340 |
| 3 | 765450 |
| 4 | 45605511 |
| 5 | 2511058725 |
| 6 | 131122437930 |
| 7 | 6597627438600 |
| 8 | 323216347675221 |
| 9 | 15525889656392115 |
| 10 | 734898808902814920 |
| 11 | 34399620992372494950 |
| 12 | 1596504028634137480131 |
| 13 | 73607593519321749694305 |