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 | 0 |
| 3 | 1 |
| 4 | -2 |
| 5 | 1 |
| 6 | 1 |
| 7 | -6 |
| 8 | 11 |
| 9 | -6 |
| 10 | 1 |
| 11 | -12 |
| 12 | 50 |
| 13 | -84 |
| 14 | 45 |
| 15 | 1 |
| 16 | -20 |
| 17 | 150 |
| 18 | -520 |
| 19 | 809 |
| 20 | -420 |
| 21 | 1 |
| 22 | -30 |
| 23 | 355 |
| 24 | -2100 |
| 25 | 6439 |
| 26 | -9390 |
| 27 | 4725 |
| 28 | 1 |
| 29 | -42 |
| 30 | 721 |
| 31 | -6510 |
| 32 | 33019 |
| 33 | -92358 |
| 34 | 127539 |
| 35 | -62370 |
| 36 | 1 |
| 37 | -56 |
| 38 | 1316 |
| 39 | -16856 |
| 40 | 127694 |
| 41 | -578984 |
| 42 | 1505524 |
| 43 | -1984584 |
| 44 | 945945 |
| 45 | 1 |
| 46 | -72 |
| 47 | 2220 |
| 48 | -38304 |
| 49 | 405174 |
| 50 | -2702448 |
| 51 | 11228300 |
| 52 | -27491616 |
| 53 | 34812945 |
| 54 | -16216200 |