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 | -9 |
| 2 | 27 |
| 3 | -30 |
| 4 | 72 |
| 5 | -387 |
| 6 | 738 |
| 7 | -801 |
| 8 | 2889 |
| 9 | -8119 |
| 10 | 13005 |
| 11 | -25038 |
| 12 | 57735 |
| 13 | -122643 |
| 14 | 247788 |
| 15 | -432786 |
| 16 | 862497 |
| 17 | -1944657 |
| 18 | 3520721 |
| 19 | -6191280 |
| 20 | 12743919 |
| 21 | -24916977 |
| 22 | 45349101 |
| 23 | -83116206 |
| 24 | 156731304 |
| 25 | -299550636 |
| 26 | 547421607 |