power calc error

[layerswing]

In galculator
263.4093759731027 * 2^(-12/1200) = 261,1833263
If I use comma the result is correct:
263,4093759731027 * 2^(-12/1200) = 261,589874507

but in java it is = 261.589874506641
class Main {
public static void main(String[] args) {
Double d_NoteFreq_TET = 263.4093759731027;
Double d_NoteFreq = 0.0;
int i_Cent = -12;
Double div = Double.valueOf(i_Cent) / 1200.0;
d_NoteFreq = d_NoteFreq_TET * Math.pow(2, div);
System.out.println("d_NoteFreq "+d_NoteFreq );
}
}
in js = 261.589874506641
https://jsfiddle.net/vr0s1h9p/

[layerswing]

This is what it does: