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 | 2 |
| 3 | -14 |
| 4 | 25 |
| 5 | -80 |
| 6 | 192 |
| 7 | -523 |
| 8 | 1346 |
| 9 | -3550 |
| 10 | 9265 |
| 11 | -24288 |
| 12 | 63552 |
| 13 | -166419 |
| 14 | 435650 |
| 15 | -1140590 |
| 16 | 2986057 |
| 17 | -7817648 |
| 18 | 20466816 |
| 19 | -53582875 |
| 20 | 140281730 |
| 21 | -367262398 |
| 22 | 961505377 |
| 23 | -2517253824 |
| 24 | 6590256000 |
| 25 | -17253514275 |
| 26 | 45170286722 |
| 27 | -118257345998 |