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 | -143 |
| 3 | 431 |
| 4 | 102817 |
| 5 | -516961 |
| 6 | -180591983 |
| 7 | 1271389391 |
| 8 | 590431841857 |
| 9 | -5344434717121 |
| 10 | -3101366777446223 |
| 11 | 34311221287283951 |
| 12 | 23891962452055766497 |
| 13 | -312381736724957870881 |
| 14 | -253773444779195937916463 |
| 15 | 3828493412657940540740111 |
| 16 | 3554513595972161589740996737 |