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 | 6 |
| 3 | -1 |
| 4 | 20 |
| 5 | 0 |
| 6 | 3 |
| 7 | 56 |
| 8 | 28 |
| 9 | 98 |
| 10 | -15 |
| 11 | 144 |
| 12 | 192 |
| 13 | 1080 |
| 14 | -48 |
| 15 | 105 |
| 16 | 352 |
| 17 | 880 |
| 18 | 7568 |
| 19 | 2024 |
| 20 | 6534 |
| 21 | -945 |
| 22 | 832 |
| 23 | 3328 |
| 24 | 40976 |
| 25 | 31616 |
| 26 | 132444 |
| 27 | -8112 |
| 28 | 10395 |
| 29 | 1920 |
| 30 | 11200 |
| 31 | 187488 |
| 32 | 274480 |
| 33 | 1593960 |
| 34 | 286900 |
| 35 | 972162 |
| 36 | -135135 |
| 37 | 4352 |
| 38 | 34816 |
| 39 | 761600 |
| 40 | 1784320 |
| 41 | 13962848 |