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 | 0 |
| 1 | -3 |
| 2 | 12 |
| 3 | -36 |
| 4 | 105 |
| 5 | -303 |
| 6 | 873 |
| 7 | -2514 |
| 8 | 7239 |
| 9 | -20844 |
| 10 | 60018 |
| 11 | -172815 |
| 12 | 497601 |
| 13 | -1432785 |
| 14 | 4125540 |
| 15 | -11879019 |
| 16 | 34204272 |
| 17 | -98487276 |
| 18 | 283582809 |
| 19 | -816544155 |
| 20 | 2351145189 |
| 21 | -6769852758 |
| 22 | 19493014119 |
| 23 | -56127897168 |
| 24 | 161613838746 |
| 25 | -465348502119 |
| 26 | 1339917609189 |
| 27 | -3858138988821 |