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) |
|---|---|
| 5 | 1 |
| 6 | 10 |
| 7 | 85 |
| 8 | 735 |
| 9 | 8449 |
| 10 | 112644 |
| 11 | 1605680 |
| 12 | 23932700 |
| 13 | 391910596 |
| 14 | 7073468688 |
| 15 | 138120962616 |
| 16 | 2862132655200 |
| 17 | 62993944853904 |
| 18 | 1476042415885824 |
| 19 | 36728281476425088 |
| 20 | 964322664638298624 |
| 21 | 26615080195964032896 |