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) |
|---|---|
| 4 | 1 |
| 5 | 5 |
| 6 | 35 |
| 7 | 140 |
| 8 | 720 |
| 9 | 2700 |
| 10 | 12375 |
| 11 | 45375 |
| 12 | 196625 |
| 13 | 715715 |
| 14 | 3006003 |
| 15 | 10930920 |
| 16 | 45048640 |
| 17 | 164105760 |
| 18 | 668144880 |
| 19 | 2441298600 |
| 20 | 9859090500 |
| 21 | 36149998500 |
| 22 | 145173803500 |
| 23 | 534239596880 |
| 24 | 2136958387520 |
| 25 | 7892175863000 |
| 26 | 31479019635375 |
| 27 | 116657543354625 |
| 28 | 464342770607625 |
| 29 | 1726402608669375 |