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 | -2 |
| 2 | 4 |
| 3 | -6 |
| 4 | -8 |
| 5 | 150 |
| 6 | -972 |
| 7 | 3682 |
| 8 | 6256 |
| 9 | -289746 |
| 10 | 3300460 |
| 11 | -21071622 |
| 12 | -27876312 |
| 13 | 3156947014 |
| 14 | -53217341660 |
| 15 | 494232431250 |
| 16 | 175171749088 |
| 17 | -113735274256290 |
| 18 | 2613309376750812 |
| 19 | -32653995355358678 |
| 20 | 36013529538641560 |
| 21 | 10227377502146048118 |
| 22 | -305630239215263764076 |