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 | 0 |
| 2 | 0 |
| 3 | 0 |
| 4 | 0 |
| 5 | 0 |
| 6 | -3 |
| 7 | 0 |
| 8 | 0 |
| 9 | 0 |
| 10 | -18 |
| 11 | -18 |
| 12 | 42 |
| 13 | 0 |
| 14 | -135 |
| 15 | -270 |
| 16 | 477 |
| 17 | 648 |
| 18 | -1980 |
| 19 | -2988 |
| 20 | 4140 |
| 21 | 14052 |
| 22 | -21690 |
| 23 | -52920 |
| 24 | 55020 |
| 25 | 201852 |
| 26 | -162774 |
| 27 | -914538 |
| 28 | 555750 |
| 29 | 3229524 |
| 30 | -1188327 |
| 31 | -13301370 |
| 32 | 1402686 |
| 33 | 52334268 |
| 34 | 95751 |
| 35 | -195398208 |
| 36 | -58983558 |
| 37 | 761838084 |
| 38 | 359664885 |
| 39 | -2910516786 |
| 40 | -1946958399 |
| 41 | 10681132140 |
| 42 | 10207745148 |
| 43 | -40522674258 |