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 | -20 |
| 2 | 190 |
| 3 | -1160 |
| 4 | 5245 |
| 5 | -19324 |
| 6 | 62150 |
| 7 | -182040 |
| 8 | 495750 |
| 9 | -1269620 |
| 10 | 3088376 |
| 11 | -7197240 |
| 12 | 16164595 |
| 13 | -35136760 |
| 14 | 74192590 |
| 15 | -152674048 |
| 16 | 306968470 |
| 17 | -604298520 |
| 18 | 1166898210 |
| 19 | -2213813640 |
| 20 | 4132159452 |
| 21 | -7597272900 |