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 | 8 |
| 4 | 30 |
| 5 | 250 |
| 6 | 548 |
| 7 | 3180 |
| 8 | 7468 |
| 9 | 20684 |
| 10 | 36164 |
| 11 | 112406 |
| 12 | 163600 |
| 13 | 425144 |
| 14 | 636208 |
| 15 | 1028934 |
| 16 | 1581766 |
| 17 | 3323182 |
| 18 | 4249976 |
| 19 | 8216442 |
| 20 | 10668790 |
| 21 | 15329216 |