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 | 48 |
| 3 | -2256 |
| 4 | 105985 |
| 5 | -4979040 |
| 6 | 233908896 |
| 7 | -10988739073 |
| 8 | 516236827536 |
| 9 | -24252142155120 |
| 10 | 1139334444463105 |
| 11 | -53524466747610816 |
| 12 | 2514510602693245248 |
| 13 | -118128473859834915841 |
| 14 | 5549523760809547799280 |
| 15 | -260709488284188911650320 |