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 | 3 |
| 5 | 11 |
| 6 | 50 |
| 7 | 634 |
| 8 | 6804 |
| 9 | 71868 |
| 10 | 789984 |
| 11 | 11025936 |
| 12 | 174509280 |
| 13 | 2940903360 |
| 14 | 51707242080 |
| 15 | 987781034304 |
| 16 | 20520063789120 |
| 17 | 456583392034560 |
| 18 | 10712403843563520 |
| 19 | 265316096850923520 |
| 20 | 6948996535924162560 |