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 | 0 |
| 4 | 1 |
| 5 | 0 |
| 6 | -1 |
| 7 | -1 |
| 8 | 0 |
| 9 | 4 |
| 10 | 8 |
| 11 | 2 |
| 12 | -34 |
| 13 | -108 |
| 14 | -160 |
| 15 | 189 |
| 16 | 2363 |
| 17 | 8032 |
| 18 | 12277 |
| 19 | -30155 |
| 20 | -347952 |
| 21 | -1464609 |
| 22 | -3099733 |
| 23 | 4975748 |
| 24 | 96347901 |
| 25 | 539113345 |
| 26 | 1751884290 |
| 27 | 714138346 |
| 28 | -40349734815 |
| 29 | -334283308597 |
| 30 | -1643012627964 |
| 31 | -4159491453450 |