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 | 0 |
| 2 | 2 |
| 3 | -3 |
| 4 | 1 |
| 5 | 0 |
| 6 | 40 |
| 7 | -180 |
| 8 | 370 |
| 9 | -455 |
| 10 | 363 |
| 11 | -190 |
| 12 | 63 |
| 13 | -12 |
| 14 | 1 |
| 15 | 0 |
| 16 | 608000 |
| 17 | -6960000 |
| 18 | 40524800 |
| 19 | -158999200 |
| 20 | 468979200 |
| 21 | -1099617480 |
| 22 | 2117585600 |
| 23 | -3419826630 |
| 24 | 4697231261 |
| 25 | -5541107684 |
| 26 | 5652058863 |
| 27 | -5007519752 |
| 28 | 3863562996 |
| 29 | -2598606825 |
| 30 | 1522861581 |
| 31 | -776022242 |
| 32 | 342624075 |
| 33 | -130362394 |
| 34 | 42424338 |
| 35 | -11689056 |
| 36 | 2689452 |
| 37 | -507084 |
| 38 | 76293 |
| 39 | -8806 |
| 40 | 732 |
| 41 | -39 |
| 42 | 1 |