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 | 1 |
| 2 | 0 |
| 3 | 2 |
| 4 | 1 |
| 5 | 0 |
| 6 | 9 |
| 7 | 5 |
| 8 | 2 |
| 9 | 0 |
| 10 | 114 |
| 11 | 84 |
| 12 | 44 |
| 13 | 17 |
| 14 | 0 |
| 15 | 6894 |
| 16 | 6348 |
| 17 | 4983 |
| 18 | 3141 |
| 19 | 1451 |
| 20 | 0 |
| 21 | 7785062 |