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) |
|---|---|
| 1 | 1 |
| 2 | -3 |
| 3 | -8 |
| 4 | 0 |
| 5 | -48 |
| 6 | 112 |
| 7 | -256 |
| 8 | 0 |
| 9 | 0 |
| 10 | 2816 |
| 11 | -6144 |
| 12 | 0 |
| 13 | -28672 |
| 14 | 61440 |
| 15 | 131072 |
| 16 | 0 |
| 17 | -589824 |
| 18 | 0 |
| 19 | -2621440 |
| 20 | 0 |
| 21 | 11534336 |
| 22 | 24117248 |
| 23 | -50331648 |
| 24 | 0 |
| 25 | 0 |
| 26 | 452984832 |
| 27 | 0 |
| 28 | 0 |
| 29 | -4026531840 |
| 30 | -8321499136 |