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 | -12 |
| 4 | 50 |
| 5 | 913 |
| 6 | -35093 |
| 7 | 557048 |
| 8 | 15098348 |
| 9 | -1975843727 |
| 10 | 103722820509 |
| 11 | -396969408196 |
| 12 | -704487440688562 |
| 13 | 106081534307130081 |
| 14 | -7995154887120369801 |
| 15 | -510404434212739199104 |
| 16 | 340061796037700870259064 |
| 17 | -75820293495741408235957599 |
| 18 | 8142099722101269515604494937 |