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 | -1 |
| 1 | 0 |
| 2 | 8 |
| 3 | 16 |
| 4 | 24 |
| 5 | 96 |
| 6 | 360 |
| 7 | 1008 |
| 8 | 2808 |
| 9 | 8640 |
| 10 | 26568 |
| 11 | 79056 |
| 12 | 235224 |
| 13 | 707616 |
| 14 | 2128680 |
| 15 | 6380208 |
| 16 | 19123128 |
| 17 | 57386880 |
| 18 | 172213128 |
| 19 | 516586896 |
| 20 | 1549603224 |
| 21 | 4648967136 |
| 22 | 13947373800 |
| 23 | 41841649008 |
| 24 | 125523529848 |
| 25 | 376572006720 |
| 26 | 1129720271688 |
| 27 | 3389156563536 |
| 28 | 10167456936024 |