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) |
|---|---|
| 4 | 0 |
| 5 | 1 |
| 6 | 0 |
| 7 | 5 |
| 8 | 0 |
| 9 | 18 |
| 10 | 0 |
| 11 | 57 |
| 12 | 0 |
| 13 | 183 |
| 14 | 0 |
| 15 | 604 |
| 16 | 0 |
| 17 | 2047 |
| 18 | 0 |
| 19 | 7145 |
| 20 | 0 |
| 21 | 25471 |
| 22 | 0 |
| 23 | 92193 |