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) |
|---|---|
| 2 | 1 |
| 3 | -16 |
| 4 | 152 |
| 5 | -1088 |
| 6 | 6444 |
| 7 | -33184 |
| 8 | 153152 |
| 9 | -646528 |
| 10 | 2533070 |
| 11 | -9311664 |
| 12 | 32387616 |
| 13 | -107299904 |
| 14 | 340436664 |
| 15 | -1039026144 |
| 16 | 3061896704 |
| 17 | -8739810688 |
| 18 | 24229115109 |
| 19 | -65390485328 |
| 20 | 172155210320 |
| 21 | -442928464640 |
| 22 | 1115433685796 |
| 23 | -2753362613984 |
| 24 | 6670224790272 |
| 25 | -15876957230848 |