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 | -2 |
| 2 | 1 |
| 3 | 6 |
| 4 | -5 |
| 5 | 1 |
| 6 | -24 |
| 7 | 26 |
| 8 | -9 |
| 9 | 1 |
| 10 | 120 |
| 11 | -154 |
| 12 | 71 |
| 13 | -14 |
| 14 | 1 |
| 15 | -720 |
| 16 | 1044 |
| 17 | -580 |
| 18 | 155 |
| 19 | -20 |
| 20 | 1 |
| 21 | 5040 |
| 22 | -8028 |
| 23 | 5104 |
| 24 | -1665 |
| 25 | 295 |
| 26 | -27 |
| 27 | 1 |
| 28 | -40320 |
| 29 | 69264 |
| 30 | -48860 |
| 31 | 18424 |
| 32 | -4025 |
| 33 | 511 |
| 34 | -35 |
| 35 | 1 |
| 36 | 362880 |
| 37 | -663696 |
| 38 | 509004 |
| 39 | -214676 |
| 40 | 54649 |
| 41 | -8624 |
| 42 | 826 |
| 43 | -44 |
| 44 | 1 |
| 45 | -3628800 |
| 46 | 6999840 |
| 47 | -5753736 |