Yes, websites. Have not gone over them completely so I do not know how good their computations are.

]]>I found a couple of pages that agree with his approach and also calculate the number for you.

]]>You can plug in the values now..]]>

I thought of something like:

and we have

Yes, yes, it seems more clear but how does it fit into the formula?

I mean how do you relate the calculation with it?

]]>You are forgetting that I did not get the answer so I must not have filled that formula in correctly.

]]>Look at his answer:

then look at the formula:

try replacing corresponding parts.

I did not see gAr's answer until I posted. He got the solution so he is the guy to ask.

]]>and we have

But how do you use that formula?

]]>That has the form of his answer. That is what I was working on, trying to fill that in but I must have missed something.

His use of the tree is better, it lends itself to computation better.

]]>