Hi. We want to print each term in the formula provided in the problem description. This is the code that does so:

for (int j = 0; j < n; j++) {
     a += b * (int) Math.pow(2, j);
     System.out.print(a + " ");
}

Try to compare the value of a in my code above to each term in the equation in the problem statement. First, for j= 0, we will get:

a + (2^0)*b

which matches the first term in the formula in the problem statement.

Try to see what we get for j=1 and j=2.

HackerRank solutions.