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) |
|---|---|
| 0 | 0 |
| 1 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 24 |
| 5 | 240 |
| 6 | 1440 |
| 7 | 6720 |
| 8 | 26880 |
| 9 | 96768 |
| 10 | 322560 |
| 11 | 1013760 |
| 12 | 3041280 |
| 13 | 8785920 |
| 14 | 24600576 |
| 15 | 67092480 |
| 16 | 178913280 |
| 17 | 467927040 |
| 18 | 1203240960 |
| 19 | 3048210432 |
| 20 | 7620526080 |
| 21 | 18827182080 |
| 22 | 46022000640 |
| 23 | 111421685760 |
| 24 | 267412045824 |
| 25 | 636695347200 |
| 26 | 1504916275200 |