Question 401664

 
We add the possibilities : if it starts with bit 1, but does not stop with 00 in order not to count doubly, we get : 2^5 for bits 2,3,4,5,6, times 3 possibilities for bits 7,8 should not equal 00, hence 32*3
 
these possibilities have to be added to all cases where the first bit is 0, and the 2 last 00, which makes bits 2,3,4,5,6 free, or 2^5=32
 

the total number of possibilities are then : 32*4=64*2=128 possibilities.