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 | 28 |
| 4 | 234 |
| 5 | 2162 |
| 6 | 21272 |
| 7 | 218740 |
| 8 | 2323730 |
| 9 | 25314097 |
| 10 | 281299736 |
| 11 | 3176220308 |
| 12 | 36332751862 |
| 13 | 420086210688 |