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 | 192 |
| 4 | -8280 |
| 5 | 147200 |
| 6 | -1438020 |
| 7 | 7491456 |
| 8 | -4626880 |
| 9 | -246965760 |
| 10 | 2112385950 |
| 11 | -9443825600 |
| 12 | 23625035616 |
| 13 | -14413771008 |
| 14 | -118710609640 |
| 15 | 427914230400 |
| 16 | -467038103040 |
| 17 | -645319017984 |
| 18 | 1640006523477 |
| 19 | 2800373100480 |
| 20 | -8506579320400 |
| 21 | -21655683517440 |
| 22 | 108181106829972 |