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) |
|---|---|
| 2 | 1 |
| 3 | -6 |
| 4 | 25 |
| 5 | -60 |
| 6 | -203 |
| 7 | 3710 |
| 8 | -21347 |
| 9 | -50400 |
| 10 | 2465969 |
| 11 | -24201342 |
| 12 | -14909791 |
| 13 | 4154706556 |
| 14 | -61829802067 |
| 15 | 107889525510 |
| 16 | 13926895008805 |
| 17 | -296622934827816 |
| 18 | 1387504872714793 |
| 19 | 80367331405832714 |
| 20 | -2381736125794455767 |
| 21 | 19480923855903871284 |
| 22 | 721535152036700012069 |
| 23 | -29550684521199839783538 |