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 |