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 | 1 |
| 3 | 1 |
| 4 | -2 |
| 5 | 1 |
| 6 | -2 |
| 7 | 5 |
| 8 | -4 |
| 9 | 1 |
| 10 | 6 |
| 11 | -16 |
| 12 | 15 |
| 13 | -6 |
| 14 | 1 |
| 15 | -30 |
| 16 | 81 |
| 17 | -79 |
| 18 | 36 |
| 19 | -9 |
| 20 | 1 |
| 21 | 204 |
| 22 | -552 |
| 23 | 543 |
| 24 | -256 |
| 25 | 72 |
| 26 | -12 |
| 27 | 1 |
| 28 | -1944 |
| 29 | 5262 |
| 30 | -5184 |
| 31 | 2461 |
| 32 | -712 |
| 33 | 132 |
| 34 | -16 |
| 35 | 1 |
| 36 | 23340 |
| 37 | -63180 |
| 38 | 62260 |
| 39 | -29596 |
| 40 | 8615 |
| 41 | -1640 |
| 42 | 220 |
| 43 | -20 |
| 44 | 1 |
| 45 | -360060 |
| 46 | 974670 |
| 47 | -960520 |
| 48 | 456700 |
| 49 | -133091 |
| 50 | 25475 |
| 51 | -3500 |
| 52 | 350 |
| 53 | -25 |
| 54 | 1 |
| 55 | 6692280 |
| 56 | -18115800 |