Why is my binary to decimal program giving incorrect outputs?

I'm working on this program that takes a binary string and converts it to decimal, using this guide to convert from binary to decimal. When I run through the for loop in my head, I get what the correct outputs would be. And yet, when I run my program, I get this strange output:

1
3
7
15
31
63
127

The actual output should look like this:

1
2
5
11
22
44
89

I cannot figure this out for the life of me. Why is my program doing this? Here's the current source code:

public class BinaryToDecimal
{
public static void main(String[] args)
{
    String binary = "1011001";
    int toMultiplyBy;
    int decimalValue = 0;
    for (int i = 1; i <= binary.length(); i++)
    {
        int whatNumber = binary.indexOf(i);
        if (whatNumber == 0)
        {
            toMultiplyBy = 0;
        }
        else
        {
            toMultiplyBy = 1;
        }
        decimalValue = ((decimalValue * 2) + toMultiplyBy);
        System.out.println(decimalValue);
        }
    }
}