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 | 1 |
| 1 | -2 |
| 2 | 3 |
| 3 | -1 |
| 4 | -11 |
| 5 | 19 |
| 6 | 151 |
| 7 | -799 |
| 8 | -2295 |
| 9 | 37367 |
| 10 | -16469 |
| 11 | -2114531 |
| 12 | 9695533 |
| 13 | 132142451 |
| 14 | -1556927553 |
| 15 | -6822608311 |
| 16 | 234527654161 |
| 17 | -360436983569 |
| 18 | -35798255259821 |
| 19 | 294290464165685 |
| 20 | 5217729367883061 |
| 21 | -102317187098688661 |
| 22 | -517822188623299097 |
| 23 | 31412148276241662049 |