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 | 3 |
| 3 | 9 |
| 4 | 15 |
| 5 | 45 |
| 6 | 105 |
| 7 | 315 |
| 8 | 945 |
| 9 | 2835 |
| 10 | 3465 |
| 11 | 10395 |
| 12 | 31185 |
| 13 | 45045 |
| 14 | 135135 |
| 15 | 405405 |
| 16 | 675675 |
| 17 | 2027025 |
| 18 | 3828825 |
| 19 | 11486475 |
| 20 | 34459425 |
| 21 | 72747675 |
| 22 | 218243025 |
| 23 | 654729075 |
| 24 | 1527701175 |
| 25 | 4583103525 |
| 26 | 11712375675 |
| 27 | 35137127025 |
| 28 | 105411381075 |