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 | 3 |
| 6 | 0 |
| 7 | 60 |
| 8 | 0 |
| 9 | 5457 |
| 10 | 2391 |
| 11 | 0 |
| 12 | 258474 |
| 13 | 3200871 |
| 14 | 37 |
| 15 | 1 |
| 16 | 0 |
| 17 | 1041762 |
| 18 | 2583730089 |
| 19 | 364670 |
| 20 | 154 |
| 21 | 0 |