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 | -6 |
| 4 | 0 |
| 5 | -30 |
| 6 | 12 |
| 7 | -210 |
| 8 | 0 |
| 9 | 0 |
| 10 | 60 |
| 11 | -2310 |
| 12 | 0 |
| 13 | -30030 |
| 14 | 420 |
| 15 | 180 |
| 16 | 0 |
| 17 | -510510 |
| 18 | 0 |
| 19 | -9699690 |
| 20 | 0 |
| 21 | 1260 |
| 22 | 4620 |
| 23 | -223092870 |
| 24 | 0 |
| 25 | 0 |
| 26 | 60060 |
| 27 | 0 |
| 28 | 0 |
| 29 | -6469693230 |
| 30 | -360 |
| 31 | -200560490130 |
| 32 | 0 |
| 33 | 13860 |
| 34 | 1021020 |
| 35 | 6300 |
| 36 | 0 |
| 37 | -7420738134810 |
| 38 | 19399380 |
| 39 | 180180 |
| 40 | 0 |
| 41 | -304250263527210 |
| 42 | -2520 |
| 43 | -13082761331670030 |
| 44 | 0 |
| 45 | 0 |
| 46 | 446185740 |
| 47 | -614889782588491410 |