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 | 31 |
| 6 | 105 |
| 7 | 1285 |
| 8 | 4599 |
| 9 | 60787 |
| 10 | 3085465 |
| 11 | 11545611 |
| 12 | 619094385 |
| 13 | 8939118925 |
| 14 | 34093383807 |
| 15 | 499069107643 |
| 16 | 28324525958305 |
| 17 | 1628420204246959 |
| 18 | 6300117511512825 |
| 19 | 367099384551433863 |
| 20 | 5542683665339959171 |