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 | 3 |
| 4 | -4 |
| 5 | 1 |
| 6 | 12 |
| 7 | -19 |
| 8 | 8 |
| 9 | -1 |
| 10 | 60 |
| 11 | -107 |
| 12 | 59 |
| 13 | -13 |
| 14 | 1 |
| 15 | 360 |
| 16 | -702 |
| 17 | 461 |
| 18 | -137 |
| 19 | 19 |
| 20 | -1 |
| 21 | 2520 |
| 22 | -5274 |
| 23 | 3929 |
| 24 | -1420 |
| 25 | 270 |
| 26 | -26 |
| 27 | 1 |
| 28 | 20160 |
| 29 | -44712 |
| 30 | 36706 |
| 31 | -15289 |
| 32 | 3580 |
| 33 | -478 |
| 34 | 34 |
| 35 | -1 |
| 36 | 181440 |
| 37 | -422568 |
| 38 | 375066 |
| 39 | -174307 |
| 40 | 47509 |
| 41 | -7882 |
| 42 | 784 |
| 43 | -43 |
| 44 | 1 |
| 45 | 1814400 |
| 46 | -4407120 |
| 47 | 4173228 |
| 48 | -2118136 |
| 49 | 649397 |
| 50 | -126329 |
| 51 | 15722 |