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 | 0 |
| 4 | -2 |
| 5 | 1 |
| 6 | 0 |
| 7 | -6 |
| 8 | 1 |
| 9 | 1 |
| 10 | 0 |
| 11 | -48 |
| 12 | -4 |
| 13 | 12 |
| 14 | 1 |
| 15 | 0 |
| 16 | -720 |
| 17 | -204 |
| 18 | 208 |
| 19 | 35 |
| 20 | 1 |
| 21 | 0 |
| 22 | -17280 |
| 23 | -7776 |
| 24 | 5208 |
| 25 | 1348 |
| 26 | 74 |
| 27 | 1 |
| 28 | 0 |
| 29 | -604800 |
| 30 | -358560 |
| 31 | 179688 |
| 32 | 64580 |
| 33 | 5138 |
| 34 | 133 |
| 35 | 1 |
| 36 | 0 |
| 37 | -29030400 |
| 38 | -20839680 |
| 39 | 8175744 |
| 40 | 3888528 |
| 41 | 400384 |
| 42 | 14952 |
| 43 | 216 |
| 44 | 1 |
| 45 | 0 |
| 46 | -1828915200 |
| 47 | -1516112640 |
| 48 | 472666752 |
| 49 | 291010032 |
| 50 | 36493200 |
| 51 | 1753624 |
| 52 | 36624 |
| 53 | 327 |
| 54 | 1 |