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) |
|---|---|
| 1 | 1 |
| 2 | -2 |
| 3 | 1 |
| 4 | -4 |
| 5 | 2 |
| 6 | 1 |
| 7 | -8 |
| 8 | 20 |
| 9 | -16 |
| 10 | 2 |
| 11 | 1 |
| 12 | -16 |
| 13 | 104 |
| 14 | -352 |
| 15 | 660 |
| 16 | -672 |
| 17 | 336 |
| 18 | -64 |
| 19 | 2 |
| 20 | 1 |
| 21 | -32 |
| 22 | 464 |
| 23 | -4032 |
| 24 | 23400 |
| 25 | -95680 |
| 26 | 283360 |
| 27 | -615296 |
| 28 | 980628 |
| 29 | -1136960 |
| 30 | 940576 |
| 31 | -537472 |
| 32 | 201552 |
| 33 | -45696 |
| 34 | 5440 |
| 35 | -256 |
| 36 | 2 |
| 37 | 1 |
| 38 | -64 |
| 39 | 1952 |
| 40 | -37760 |
| 41 | 520144 |
| 42 | -5430656 |
| 43 | 44662464 |