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 | -4 |
| 2 | 16 |
| 3 | -48 |
| 4 | 112 |
| 5 | -248 |
| 6 | 576 |
| 7 | -1248 |
| 8 | 2272 |
| 9 | -3988 |
| 10 | 8672 |
| 11 | -18192 |
| 12 | 23616 |
| 13 | -23000 |
| 14 | 100992 |
| 15 | -304032 |
| 16 | 41152 |
| 17 | 970552 |
| 18 | 1972816 |
| 19 | -11299824 |
| 20 | -9904096 |
| 21 | 80729472 |
| 22 | 95978688 |
| 23 | -676487328 |
| 24 | -755649408 |
| 25 | 5483063076 |
| 26 | 6371808608 |
| 27 | -45452602080 |
| 28 | -53224627584 |
| 29 | 378628636264 |
| 30 | 449486486400 |
| 31 | -3179963494272 |