The following is based on Waring's Problem:
For all n  floor((3/2)^n) + 3^n mod 2^n < 2^n. Kubina has tested this up to 471,600,000.

x = 9;
for( y = 4 ; x/y + x%y < y ; y *= z )
   x *= 3;

Assume that x and y are int's with unlimited size.