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 | 2 |
| 3 | 1 |
| 4 | 3 |
| 5 | -1 |
| 6 | 15 |
| 7 | -78 |
| 8 | 632 |
| 9 | -6049 |
| 10 | 68036 |
| 11 | -878337 |
| 12 | 12817659 |
| 13 | -208803098 |
| 14 | 3758607935 |
| 15 | -74132077726 |
| 16 | 1590647874073 |