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 | 7 |
| 3 | 26 |
| 4 | 50 |
| 5 | 24 |
| 6 | -24 |
| 7 | 48 |
| 8 | -144 |
| 9 | 576 |
| 10 | -2880 |
| 11 | 17280 |
| 12 | -120960 |
| 13 | 967680 |
| 14 | -8709120 |
| 15 | 87091200 |
| 16 | -958003200 |
| 17 | 11496038400 |
| 18 | -149448499200 |
| 19 | 2092278988800 |
| 20 | -31384184832000 |
| 21 | 502146957312000 |
| 22 | -8536498274304000 |
| 23 | 153656968937472000 |
| 24 | -2919482409811968000 |
| 25 | 58389648196239360000 |