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 | -2 |
| 3 | 1 |
| 4 | -28 |
| 5 | 29 |
| 6 | -194 |
| 7 | 1583 |
| 8 | -61328 |
| 9 | 144153 |
| 10 | -1697262 |
| 11 | 20127867 |
| 12 | -191762088 |
| 13 | 3978820221 |
| 14 | -66586416948 |
| 15 | 1057400360235 |
| 16 | -58260102945024 |
| 17 | 370244721585681 |
| 18 | -7992573879248406 |
| 19 | 162968423791332339 |
| 20 | -3399970067764816824 |
| 21 | 88052648301403014789 |
| 22 | -2360852841450177138924 |