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 | 0 |
| 1 | 1 |
| 2 | 1 |
| 3 | 0 |
| 4 | 1 |
| 5 | -2 |
| 6 | -6 |
| 7 | 0 |
| 8 | -2 |
| 9 | 12 |
| 10 | 24 |
| 11 | 36 |
| 12 | 0 |
| 13 | 6 |
| 14 | -72 |
| 15 | -240 |
| 16 | -240 |
| 17 | -240 |
| 18 | 0 |
| 19 | -24 |
| 20 | 600 |
| 21 | 2160 |
| 22 | 3600 |
| 23 | 2400 |
| 24 | 1800 |
| 25 | 0 |
| 26 | 120 |
| 27 | -5760 |
| 28 | -25200 |
| 29 | -45360 |
| 30 | -50400 |
| 31 | -25200 |
| 32 | -15120 |
| 33 | 0 |
| 34 | -720 |
| 35 | 65520 |
| 36 | 322560 |
| 37 | 705600 |
| 38 | 846720 |
| 39 | 705600 |
| 40 | 282240 |
| 41 | 141120 |
| 42 | 0 |
| 43 | 5040 |