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) |
|---|---|
| 1 | 1 |
| 2 | 1 |
| 3 | 2 |
| 4 | 24 |
| 5 | -11 |
| 6 | 1085 |
| 7 | -2542 |
| 8 | 64344 |
| 9 | -56415 |
| 10 | 4275137 |
| 11 | -10660486 |
| 12 | 945005248 |
| 13 | -6010194555 |
| 14 | 147121931021 |
| 15 | 88135620922 |
| 16 | 23131070531152 |
| 17 | -120142133444319 |
| 18 | 12007306976370081 |
| 19 | -103897545509370542 |
| 20 | 4923827766711915784 |
| 21 | -19471338470911446283 |
| 22 | 1203786171449486366205 |