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 | -18 |
| 2 | 153 |
| 3 | -834 |
| 4 | 3384 |
| 5 | -11340 |
| 6 | 33729 |
| 7 | -92430 |
| 8 | 236727 |
| 9 | -572120 |
| 10 | 1318743 |
| 11 | -2922948 |
| 12 | 6259641 |
| 13 | -13000770 |
| 14 | 26283159 |
| 15 | -51879720 |
| 16 | 100210041 |
| 17 | -189775800 |
| 18 | 352975681 |
| 19 | -645780060 |
| 20 | 1163610432 |
| 21 | -2067225594 |
| 22 | 3624593265 |
| 23 | -6277838652 |