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 | -4 |
| 5 | 1 |
| 6 | 21 |
| 7 | 3 |
| 8 | -9 |
| 9 | 1 |
| 10 | -111 |
| 11 | 144 |
| 12 | 30 |
| 13 | -16 |
| 14 | 1 |
| 15 | -345 |
| 16 | -1599 |
| 17 | 450 |
| 18 | 110 |
| 19 | -25 |
| 20 | 1 |
| 21 | 14895 |
| 22 | 2844 |
| 23 | -9549 |
| 24 | 840 |
| 25 | 285 |
| 26 | -36 |
| 27 | 1 |
| 28 | -143955 |
| 29 | 208179 |
| 30 | 62181 |
| 31 | -36309 |
| 32 | 735 |
| 33 | 609 |
| 34 | -49 |
| 35 | 1 |
| 36 | -760095 |
| 37 | -3824064 |
| 38 | 1147068 |
| 39 | 442176 |
| 40 | -103194 |
| 41 | -1344 |
| 42 | 1148 |
| 43 | -64 |
| 44 | 1 |
| 45 | 49774095 |
| 46 | 10955169 |
| 47 | -39242556 |
| 48 | 2925180 |
| 49 | 2008314 |
| 50 | -236250 |
| 51 | -8316 |
| 52 | 1980 |
| 53 | -81 |
| 54 | 1 |
| 55 | -699437025 |
| 56 | 1080622620 |
| 57 | 384913701 |
| 58 | -238086000 |