Checking three values are consecutive
I don't like the idea of having to solve Diophantine equations just to be able to understand the code.  I'll suggest the same solution here as I did for @cody.codes:

public static boolean isSequential(int a, int b, int c) {
    int min = Math.min(a, Math.min(b, c));
    int max = Math.max(a, Math.max(b, c));
    return max - min == 2 &amp;&amp; a != b &amp;&amp; a != c &amp;&amp; b != c;
}


"The minimum and maximum differ by 2, and all three numbers are unique" is easier to understand.