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 | -1 |
| 2 | 1 |
| 3 | 10 |
| 4 | -2 |
| 5 | 1 |
| 6 | -270 |
| 7 | 24 |
| 8 | -3 |
| 9 | 1 |
| 10 | 14056 |
| 11 | -720 |
| 12 | 44 |
| 13 | -4 |
| 14 | 1 |
| 15 | -1197000 |
| 16 | 40320 |
| 17 | -1500 |
| 18 | 70 |
| 19 | -5 |
| 20 | 1 |
| 21 | 151169040 |
| 22 | -3628800 |
| 23 | 92064 |
| 24 | -2700 |
| 25 | 102 |
| 26 | -6 |
| 27 | 1 |
| 28 | -26521775280 |
| 29 | 479001600 |
| 30 | -8890560 |
| 31 | 181888 |
| 32 | -4410 |
| 33 | 140 |
| 34 | -7 |
| 35 | 1 |
| 36 | 6169461217920 |
| 37 | -87178291200 |
| 38 | 1241982720 |
| 39 | -18910080 |
| 40 | 324912 |
| 41 | -6720 |
| 42 | 184 |
| 43 | -8 |
| 44 | 1 |