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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 1 |
| 4 | 0 |
| 5 | 8 |
| 6 | -5 |
| 7 | -51 |
| 8 | -504 |
| 9 | 8224 |
| 10 | -12865 |
| 11 | -296155 |
| 12 | -2166736 |
| 13 | 73348780 |
| 14 | -116217309 |
| 15 | -7440979651 |
| 16 | -39733320080 |
| 17 | 2564082122752 |
| 18 | -3056854891489 |
| 19 | -544155777899859 |
| 20 | -2138400746459448 |
| 21 | 251904027415707852 |
| 22 | -163714875656114029 |
| 23 | -92626483427571793931 |
| 24 | -273784346863222483272 |