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 | -4 |
| 3 | -1 |
| 4 | -9 |
| 5 | 3 |
| 6 | -22 |
| 7 | 19 |
| 8 | -60 |
| 9 | 76 |
| 10 | -177 |
| 11 | 269 |
| 12 | -547 |
| 13 | 908 |
| 14 | -1733 |
| 15 | 3002 |
| 16 | -5560 |
| 17 | 9831 |
| 18 | -17949 |
| 19 | 32051 |
| 20 | -58118 |
| 21 | 104271 |
| 22 | -188456 |
| 23 | 338880 |
| 24 | -611521 |
| 25 | 1100825 |
| 26 | -1984987 |
| 27 | 3575116 |
| 28 | -6444265 |
| 29 | 11609510 |
| 30 | -20922924 |