Looping and generally awkward scenarios

[SeanV]

Hey guys, I have an exam in C programming I'm a little stuck on loops...

I have to make a program that multiplies the loop variable by 2 then takes away 1... easy, that was a for loop no problem

for (x=3; x<=65; x=x*2-1)

that should print out 3 5 9 17 33 65

however, my lecturer has given the task for it to reverse, but not to display the number 17 on the way back down using an if statement...
however, this time it must be a do while loop... This is what I have so far.

#include <stdio.h>
#include <stdlib.h>


int main()
{
    int x = 129;


    do
    {
        x = (x/2) + 1;
        
        printf("%d \n", x);


    }
    while (x >= 4);


    return 0;
}