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 | -1 |
| 2 | 10 |
| 3 | 36 |
| 4 | 40 |
| 5 | -160 |
| 6 | -1152 |
| 7 | -4480 |
| 8 | -13568 |
| 9 | -34560 |
| 10 | -74240 |
| 11 | -123904 |
| 12 | -92160 |
| 13 | 425984 |
| 14 | 2867200 |
| 15 | 11796480 |
| 16 | 40763392 |
| 17 | 128122880 |
| 18 | 378667008 |
| 19 | 1070858240 |
| 20 | 2928148480 |
| 21 | 7795113984 |
| 22 | 20300431360 |
| 23 | 51900317696 |
| 24 | 130610626560 |
| 25 | 324219699200 |
| 26 | 795206483968 |
| 27 | 1929715384320 |