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 | -5 |
| 4 | -5 |
| 5 | -21 |
| 6 | 11 |
| 7 | -53 |
| 8 | -53 |
| 9 | -53 |
| 10 | 459 |
| 11 | -565 |
| 12 | -565 |
| 13 | -4661 |
| 14 | 3531 |
| 15 | 19915 |
| 16 | 19915 |
| 17 | -45621 |
| 18 | -45621 |
| 19 | -307765 |
| 20 | -307765 |
| 21 | 740811 |
| 22 | 2837963 |
| 23 | -1356341 |
| 24 | -1356341 |
| 25 | -1356341 |
| 26 | 32198091 |
| 27 | 32198091 |
| 28 | 32198091 |
| 29 | -236237365 |
| 30 | -773108277 |