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 | 3 |
| 2 | -6 |
| 3 | 8 |
| 4 | -18 |
| 5 | 48 |
| 6 | -124 |
| 7 | 312 |
| 8 | -810 |
| 9 | 2184 |
| 10 | -5928 |
| 11 | 16104 |
| 12 | -44220 |
| 13 | 122640 |
| 14 | -341796 |
| 15 | 956576 |
| 16 | -2690010 |
| 17 | 7596480 |
| 18 | -21524412 |
| 19 | 61171656 |
| 20 | -174336264 |
| 21 | 498111952 |
| 22 | -1426419852 |
| 23 | 4093181688 |
| 24 | -11767874940 |
| 25 | 33891544368 |
| 26 | -97764131640 |