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 | 2 |
| 4 | 3 |
| 5 | 12 |
| 6 | 20 |
| 7 | 60 |
| 8 | 210 |
| 9 | 840 |
| 10 | 504 |
| 11 | 2520 |
| 12 | 27720 |
| 13 | 27720 |
| 14 | 51480 |
| 15 | 360360 |
| 16 | 180180 |
| 17 | 720720 |
| 18 | 4084080 |
| 19 | 12252240 |
| 20 | 232792560 |
| 21 | 232792560 |
| 22 | 21162960 |
| 23 | 232792560 |
| 24 | 5354228880 |
| 25 | 5354228880 |
| 26 | 2059318800 |
| 27 | 26771144400 |
| 28 | 80313433200 |
| 29 | 80313433200 |