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 | 2 |
| 1 | 1 |
| 2 | 1 |
| 3 | -3 |
| 4 | 7 |
| 5 | 15 |
| 6 | -39 |
| 7 | -307 |
| 8 | 917 |
| 9 | 2540 |
| 10 | -16939 |
| 11 | -25016 |
| 12 | 441962 |
| 13 | -498346 |
| 14 | -10210949 |
| 15 | 42714405 |
| 16 | 195220459 |
| 17 | -2142879945 |
| 18 | 532985665 |
| 19 | 83535107090 |
| 20 | -365902332521 |
| 21 | -2233273290797 |
| 22 | 28143121253695 |
| 23 | -20874136499710 |
| 24 | -1436795595314700 |
| 25 | 8862053852144592 |
| 26 | 38496064560804831 |