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 | 3 |
| 3 | -2 |
| 4 | 9 |
| 5 | -9 |
| 6 | 1 |
| 7 | 27 |
| 8 | -36 |
| 9 | 4 |
| 10 | 6 |
| 11 | 81 |
| 12 | -135 |
| 13 | 15 |
| 14 | 45 |
| 15 | -5 |
| 16 | 243 |
| 17 | -486 |
| 18 | 54 |
| 19 | 243 |
| 20 | -36 |
| 21 | -18 |
| 22 | 1 |
| 23 | 729 |
| 24 | -1701 |
| 25 | 189 |
| 26 | 1134 |
| 27 | -189 |
| 28 | -189 |
| 29 | 7 |
| 30 | 21 |
| 31 | 2187 |
| 32 | -5832 |
| 33 | 648 |
| 34 | 4860 |
| 35 | -864 |
| 36 | -1296 |
| 37 | 36 |
| 38 | 216 |
| 39 | 54 |
| 40 | -8 |
| 41 | 6561 |
| 42 | -19683 |
| 43 | 2187 |
| 44 | 19683 |
| 45 | -3645 |
| 46 | -7290 |
| 47 | 162 |
| 48 | 1458 |
| 49 | 729 |
| 50 | -81 |
| 51 | -81 |
| 52 | 1 |
| 53 | 19683 |
| 54 | -65610 |
| 55 | 7290 |
| 56 | 76545 |
| 57 | -14580 |
| 58 | -36450 |
| 59 | 675 |
| 60 | 8100 |
| 61 | 6075 |
| 62 | -540 |
| 63 | -1080 |
| 64 | 10 |
| 65 | -162 |
| 66 | 45 |