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 | -1 |
| 4 | -2 |
| 5 | 1 |
| 6 | -2 |
| 7 | 0 |
| 8 | -6 |
| 9 | 1 |
| 10 | -3 |
| 11 | 0 |
| 12 | 18 |
| 13 | -12 |
| 14 | 1 |
| 15 | -4 |
| 16 | 0 |
| 17 | -40 |
| 18 | 80 |
| 19 | -20 |
| 20 | 1 |
| 21 | -5 |
| 22 | 0 |
| 23 | 75 |
| 24 | -400 |
| 25 | 225 |
| 26 | -30 |
| 27 | 1 |
| 28 | -6 |
| 29 | 0 |
| 30 | -126 |
| 31 | 1680 |
| 32 | -1890 |
| 33 | 504 |
| 34 | -42 |
| 35 | 1 |
| 36 | -7 |
| 37 | 0 |
| 38 | 196 |
| 39 | -6272 |
| 40 | 13230 |
| 41 | -6272 |
| 42 | 980 |
| 43 | -56 |
| 44 | 1 |
| 45 | -8 |
| 46 | 0 |
| 47 | -288 |
| 48 | 21504 |
| 49 | -81648 |
| 50 | 64512 |
| 51 | -16800 |
| 52 | 1728 |
| 53 | -72 |
| 54 | 1 |
| 55 | -9 |
| 56 | 0 |
| 57 | 405 |