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 | 21 |
| 3 | 165 |
| 4 | 1274 |
| 5 | 9435 |
| 6 | 69720 |
| 7 | 515230 |
| 8 | 3807265 |
| 9 | 28132035 |
| 10 | 207869515 |
| 11 | 1535959665 |
| 12 | 11349295155 |
| 13 | 83860579775 |