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 | 3 |
| 2 | 15 |
| 3 | 45 |
| 4 | 315 |
| 5 | 3465 |
| 6 | 45045 |
| 7 | 135135 |
| 8 | 675675 |
| 9 | 11486475 |
| 10 | 218243025 |
| 11 | 5019589575 |
| 12 | 145568097675 |
| 13 | 4512611027925 |
| 14 | 31588277195475 |
| 15 | 94764831586425 |
| 16 | 3506298768697725 |
| 17 | 143758249516606725 |
| 18 | 6181604729214089175 |