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 | 0 |
| 2 | 1 |
| 3 | 0 |
| 4 | 6 |
| 5 | -2 |
| 6 | 0 |
| 7 | 48 |
| 8 | -30 |
| 9 | 9 |
| 10 | 0 |
| 11 | 500 |
| 12 | -432 |
| 13 | 252 |
| 14 | -64 |
| 15 | 0 |
| 16 | 6480 |
| 17 | -6860 |
| 18 | 5760 |
| 19 | -2880 |
| 20 | 625 |
| 21 | 0 |
| 22 | 100842 |
| 23 | -122880 |
| 24 | 131220 |
| 25 | -96000 |
| 26 | 41250 |
| 27 | -7776 |
| 28 | 0 |
| 29 | 1835008 |
| 30 | -2480058 |
| 31 | 3150000 |
| 32 | -2981440 |
| 33 | 1890000 |
| 34 | -707616 |
| 35 | 117649 |
| 36 | 0 |
| 37 | 38263752 |
| 38 | -56000000 |
| 39 | 81169704 |
| 40 | -92897280 |
| 41 | 76895000 |
| 42 | -42674688 |
| 43 | 14117880 |
| 44 | -2097152 |