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 | 0 |
| 2 | -3 |
| 3 | 15 |
| 4 | 42 |
| 5 | -2895 |
| 6 | 54417 |
| 7 | -251160 |
| 8 | -32268603 |
| 9 | 1859064495 |
| 10 | -56137896318 |
| 11 | -300966155655 |
| 12 | 194418466667697 |
| 13 | -17000801954550960 |
| 14 | 829654990634826717 |
| 15 | 8111862191577165855 |
| 16 | -7601061861134689474758 |
| 17 | 1057729211267718608758065 |