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 | -6 |
| 2 | 9 |
| 3 | -2 |
| 4 | 42 |
| 5 | -132 |
| 6 | 95 |
| 7 | -210 |
| 8 | 840 |
| 9 | -1394 |
| 10 | 2442 |
| 11 | -4374 |
| 12 | 8589 |
| 13 | -20862 |
| 14 | 31812 |
| 15 | -48758 |
| 16 | 119856 |
| 17 | -222228 |
| 18 | 347038 |
| 19 | -631992 |
| 20 | 1220781 |
| 21 | -2228812 |
| 22 | 3730962 |
| 23 | -6390948 |
| 24 | 11861066 |
| 25 | -21539358 |
| 26 | 35874624 |
| 27 | -59882714 |
| 28 | 110055054 |