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 | 0 |
| 3 | 16 |
| 4 | 0 |
| 5 | -56 |
| 6 | 0 |
| 7 | 160 |
| 8 | 0 |
| 9 | -404 |
| 10 | 0 |
| 11 | 944 |
| 12 | 0 |
| 13 | -2072 |
| 14 | 0 |
| 15 | 4320 |
| 16 | 0 |
| 17 | -8648 |
| 18 | 0 |
| 19 | 16720 |
| 20 | 0 |
| 21 | -31360 |
| 22 | 0 |
| 23 | 57312 |
| 24 | 0 |
| 25 | -102364 |
| 26 | 0 |
| 27 | 179104 |
| 28 | 0 |
| 29 | -307672 |
| 30 | 0 |
| 31 | 519808 |
| 32 | 0 |
| 33 | -864960 |
| 34 | 0 |
| 35 | 1419456 |
| 36 | 0 |
| 37 | -2299832 |
| 38 | 0 |
| 39 | 3682400 |
| 40 | 0 |
| 41 | -5831784 |
| 42 | 0 |
| 43 | 9141808 |
| 44 | 0 |
| 45 | -14194200 |
| 46 | 0 |
| 47 | 21842368 |
| 48 | 0 |