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) |
|---|---|
| 3 | 1 |
| 4 | 0 |
| 5 | 1 |
| 6 | 0 |
| 7 | 7 |
| 8 | 0 |
| 9 | 39 |
| 10 | 0 |
| 11 | 419 |
| 12 | 0 |
| 13 | 7208 |
| 14 | 0 |
| 15 | 226512 |
| 16 | 0 |
| 17 | 7885970 |
| 18 | 0 |
| 19 | 345718580 |
| 20 | 0 |
| 21 | 18478915794 |
| 22 | 0 |