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 | -7 |
| 4 | 76 |
| 5 | -989 |
| 6 | 15289 |
| 7 | -275807 |
| 8 | 5702887 |
| 9 | -133121449 |
| 10 | 3464398070 |
| 11 | -99482086439 |
| 12 | 3125039826481 |
| 13 | -106610733533317 |
| 14 | 3925411300203301 |
| 15 | -155161278879431551 |
| 16 | 6553471162481684656 |