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) |
|---|---|
| 0 | 1 |
| 1 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 0 |
| 5 | 3 |
| 6 | 1 |
| 7 | 3 |
| 8 | 12 |
| 9 | 15 |
| 10 | 10 |
| 11 | 1 |
| 12 | 40 |
| 13 | 180 |
| 14 | 297 |
| 15 | 180 |
| 16 | 60 |
| 17 | 10 |
| 18 | 1 |