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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 1 |
| 6 | -15 |
| 7 | 175 |
| 8 | -1960 |
| 9 | 22449 |
| 10 | -269199 |
| 11 | 3410000 |
| 12 | -45753180 |
| 13 | 650179816 |
| 14 | -9771920158 |
| 15 | 155020385156 |
| 16 | -2589888417480 |
| 17 | 45461879164584 |
| 18 | -836540418765834 |
| 19 | 16099972965770778 |
| 20 | -323385447259166454 |
| 21 | 6764948641797695496 |
| 22 | -147088325599708573080 |