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 | 0 |
| 1 | 1 |
| 2 | -1 |
| 3 | -2 |
| 4 | 2 |
| 5 | 13 |
| 6 | -16 |
| 7 | -161 |
| 8 | 170 |
| 9 | 2647 |
| 10 | -1711 |
| 11 | -51248 |
| 12 | 5711 |
| 13 | 1103710 |
| 14 | 599246 |
| 15 | -25521869 |
| 16 | -33907174 |
| 17 | 620323849 |
| 18 | 1410745127 |
| 19 | -15678980390 |
| 20 | -53746958146 |
| 21 | 411344661913 |
| 22 | 1998823108706 |
| 23 | -11256049308869 |
| 24 | -75003366373495 |
| 25 | 323285264486686 |
| 26 | 2904292324907387 |