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) |
|---|---|
| 5 | 1 |
| 6 | -9 |
| 7 | 112 |
| 8 | -1064 |
| 9 | 12873 |
| 10 | -140595 |
| 11 | 1870385 |
| 12 | -23551110 |
| 13 | 351042406 |
| 14 | -5043110072 |
| 15 | 84074954600 |
| 16 | -1361614072000 |
| 17 | 25218570009424 |
| 18 | -455365645674480 |
| 19 | 9298765013106384 |
| 20 | -185409487083100320 |
| 21 | 4144212593899945056 |
| 22 | -90492302454898284864 |
| 23 | 2199399908894486591040 |