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 | -3 |
| 5 | 2 |
| 6 | 1 |
| 7 | 3 |
| 8 | -10 |
| 9 | 6 |
| 10 | -1 |
| 11 | 9 |
| 12 | 10 |
| 13 | -42 |
| 14 | 24 |
| 15 | -17 |
| 16 | 21 |
| 17 | 50 |
| 18 | 42 |
| 19 | -216 |
| 20 | 120 |
| 21 | -107 |
| 22 | -33 |
| 23 | 230 |
| 24 | 294 |
| 25 | 216 |
| 26 | -1320 |
| 27 | 720 |
| 28 | -415 |
| 29 | -1173 |
| 30 | 670 |
| 31 | 1974 |
| 32 | 1944 |
| 33 | 1320 |
| 34 | -9360 |
| 35 | 5040 |
| 36 | 1231 |
| 37 | -13515 |
| 38 | -4510 |
| 39 | 11130 |
| 40 | 17064 |
| 41 | 14520 |
| 42 | 9360 |
| 43 | -75600 |
| 44 | 40320 |
| 45 | 56671 |
| 46 | -113739 |
| 47 | -131230 |
| 48 | 20202 |
| 49 | 136296 |
| 50 | 157080 |
| 51 | 121680 |
| 52 | 75600 |