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) |
|---|---|
| 2 | 0 |
| 3 | 0 |
| 4 | 3 |
| 5 | 20 |
| 6 | 0 |
| 7 | 6 |
| 8 | 56 |
| 9 | 0 |
| 10 | 9 |
| 11 | 110 |
| 12 | 1848 |
| 13 | 12 |
| 14 | 208 |
| 15 | 210 |
| 16 | 270 |
| 17 | 272 |
| 18 | 0 |
| 19 | 124182 |
| 20 | 16017 |