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 | 6 |
| 3 | 1 |
| 4 | -12 |
| 5 | 30 |
| 6 | -1 |
| 7 | 18 |
| 8 | -90 |
| 9 | 140 |
| 10 | 1 |
| 11 | -24 |
| 12 | 180 |
| 13 | -560 |
| 14 | 630 |
| 15 | -1 |
| 16 | 30 |
| 17 | -300 |
| 18 | 1400 |
| 19 | -3150 |
| 20 | 2772 |
| 21 | 1 |
| 22 | -36 |
| 23 | 450 |
| 24 | -2800 |
| 25 | 9450 |
| 26 | -16632 |
| 27 | 12012 |
| 28 | -1 |
| 29 | 42 |
| 30 | -630 |
| 31 | 4900 |
| 32 | -22050 |
| 33 | 58212 |
| 34 | -84084 |
| 35 | 51480 |
| 36 | 1 |
| 37 | -48 |
| 38 | 840 |
| 39 | -7840 |
| 40 | 44100 |
| 41 | -155232 |
| 42 | 336336 |
| 43 | -411840 |
| 44 | 218790 |