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 | 3 |
| 3 | 20 |
| 4 | 128 |
| 5 | 1269 |
| 6 | 13019 |
| 7 | 179816 |
| 8 | 2561280 |
| 9 | 45580073 |
| 10 | 831425459 |
| 11 | 18116729724 |
| 12 | 402900613376 |
| 13 | 10389410535965 |