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 | 40 |
| 5 | 1210 |
| 6 | 33880 |
| 7 | 925771 |
| 8 | 25095280 |
| 9 | 678468820 |
| 10 | 18326727760 |
| 11 | 494894285941 |
| 12 | 13362799477720 |
| 13 | 360801469802830 |
| 14 | 9741692640081640 |
| 15 | 263026177881648511 |
| 16 | 7101711092201899360 |
| 17 | 191746238094034963240 |
| 18 | 5177148775980218655520 |
| 19 | 139783020078437440101481 |