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 | 1 |
| 3 | 0 |
| 4 | -1 |
| 5 | 2 |
| 6 | 0 |
| 7 | 4 |
| 8 | -9 |
| 9 | 6 |
| 10 | 0 |
| 11 | -33 |
| 12 | 82 |
| 13 | -72 |
| 14 | 24 |
| 15 | 0 |
| 16 | 456 |
| 17 | -1225 |
| 18 | 1250 |
| 19 | -600 |
| 20 | 120 |
| 21 | 0 |
| 22 | -9460 |
| 23 | 27041 |
| 24 | -30600 |
| 25 | 17700 |
| 26 | -5400 |
| 27 | 720 |
| 28 | 0 |
| 29 | 274800 |
| 30 | -826336 |
| 31 | 1011017 |
| 32 | -661500 |
| 33 | 249900 |
| 34 | -52920 |
| 35 | 5040 |
| 36 | 0 |
| 37 | -10643745 |
| 38 | 33391954 |
| 39 | -43471624 |
| 40 | 31149496 |
| 41 | -13524000 |
| 42 | 3622080 |
| 43 | -564480 |
| 44 | 40320 |