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 | 3 |
| 4 | -5 |
| 5 | 1 |
| 6 | 9 |
| 7 | -21 |
| 8 | 12 |
| 9 | -1 |
| 10 | 27 |
| 11 | -81 |
| 12 | 75 |
| 13 | -22 |
| 14 | 1 |
| 15 | 81 |
| 16 | -297 |
| 17 | 378 |
| 18 | -195 |
| 19 | 35 |
| 20 | -1 |
| 21 | 243 |
| 22 | -1053 |
| 23 | 1701 |
| 24 | -1260 |
| 25 | 420 |
| 26 | -51 |
| 27 | 1 |
| 28 | 729 |
| 29 | -3645 |
| 30 | 7128 |
| 31 | -6885 |
| 32 | 3402 |
| 33 | -798 |
| 34 | 70 |
| 35 | -1 |
| 36 | 2187 |
| 37 | -12393 |
| 38 | 28431 |
| 39 | -33858 |
| 40 | 22275 |
| 41 | -7938 |
| 42 | 1386 |
| 43 | -92 |
| 44 | 1 |
| 45 | 6561 |