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 | 0 |
| 3 | 1 |
| 4 | -1 |
| 5 | 5 |
| 6 | 1 |
| 7 | -17 |
| 8 | 1045 |
| 9 | -35801 |
| 10 | 1 |
| 11 | -181 |
| 12 | 104905 |
| 13 | -38432557 |
| 14 | 15859708705 |
| 15 | 1 |
| 16 | -5197 |
| 17 | 82178809 |
| 18 | -864396960373 |
| 19 | 9983212589988481 |
| 20 | -112929359515545345757 |
| 21 | 1 |
| 22 | -4129 |
| 23 | 101866157 |
| 24 | -213193733657 |
| 25 | 15527707142596399 |
| 26 | -138932602159504972471 |
| 27 | 2493923095641600267646643 |
| 28 | 1 |