Search for common multiples of Voyager polynomials with few monomials: http://math.stackexchange.com/questions/177465

Question177465.java

import java.util.BitSet;

public class Question177465 {
    static BitSet [] bits = {new BitSet (),new BitSet ()};
    static int [] polynomials = {Integer.parseInt ("1011011",2),Integer.parseInt ("1111001",2)};

    public static void main (String [] args) {
        bits [0] = new BitSet ();
        bits [1] = new BitSet ();

        recurse (true,0,0);
    }

    static void recurse (boolean set,int index,int count) {
        if (set)
            add (index);

        for (int i = 0;i < 2;i++)
            if (bits [i].get (index))
                count++;

        if (count < 10) {
            recurse (true,index + 1,count);
            recurse (false,index + 1,count);
        }

        if (set)
            add (index);
    }

    static void add (int index) {
        for (int i = 0;i < 2;i++)
            for (int bit = 0,polynomial = polynomials [i];polynomial != 0;polynomial >>= 1,bit++)
                if ((polynomial & 1) == 1)
                    bits [i].flip (index + bit);
    }
}