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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 5 |
| 4 | 35 |
| 5 | 315 |
| 6 | 3465 |
| 7 | 45045 |
| 8 | 675675 |
| 9 | 11486475 |
| 10 | 218243025 |
| 11 | 4583103525 |
| 12 | 105411381075 |
| 13 | 2635284526875 |
| 14 | 71152682225625 |
| 15 | 2063427784543125 |
| 16 | 63966261320836875 |
| 17 | 2110886623587616875 |
| 18 | 73881031825566590625 |