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) |
|---|---|
| 1 | 1 |
| 2 | -1 |
| 3 | 1 |
| 4 | 1 |
| 5 | -2 |
| 6 | 1 |
| 7 | -3 |
| 8 | 3 |
| 9 | -3 |
| 10 | 1 |
| 11 | 9 |
| 12 | -12 |
| 13 | 6 |
| 14 | -4 |
| 15 | 1 |
| 16 | -45 |
| 17 | 45 |
| 18 | -30 |
| 19 | 10 |
| 20 | -5 |
| 21 | 1 |
| 22 | 225 |
| 23 | -270 |
| 24 | 135 |
| 25 | -60 |
| 26 | 15 |
| 27 | -6 |
| 28 | 1 |
| 29 | -1575 |
| 30 | 1575 |
| 31 | -945 |
| 32 | 315 |
| 33 | -105 |
| 34 | 21 |
| 35 | -7 |
| 36 | 1 |
| 37 | 11025 |
| 38 | -12600 |
| 39 | 6300 |
| 40 | -2520 |
| 41 | 630 |
| 42 | -168 |
| 43 | 28 |
| 44 | -8 |
| 45 | 1 |
| 46 | -99225 |
| 47 | 99225 |
| 48 | -56700 |
| 49 | 18900 |
| 50 | -5670 |
| 51 | 1134 |
| 52 | -252 |
| 53 | 36 |
| 54 | -9 |
| 55 | 1 |
| 56 | 893025 |
| 57 | -992250 |
| 58 | 496125 |
| 59 | -189000 |
| 60 | 47250 |
| 61 | -11340 |
| 62 | 1890 |
| 63 | -360 |
| 64 | 45 |
| 65 | -10 |
| 66 | 1 |