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 | 9 |
| 3 | 15 |
| 4 | 45 |
| 5 | 225 |
| 6 | 639 |
| 7 | 1275 |
| 8 | 4005 |
| 9 | 675405 |
| 10 | 2203959 |
| 11 | 3075159 |
| 12 | 6195234165 |
| 13 | 77989711185 |
| 14 | 4566262987329 |