if you dont want to use excel...................
Its a sequence. and the sequence iS = (first term)*(1 - r^n)/(1-r)
The first term is 1, r is ratio, 2. and n is the number of terms, 31
so (1-2^31)/(1-2) = 2,147,483,647 pennys
Which is $21,474,836.47
But my guess is that your parents would have caught on by day 15 when they were giving you 32,768 penny = $327.68
It's sad that I'm doing this. I need a job! oh wait, I am at work.