Path mapper or something else?

I can't seem to write up a definition for path mapper that would do..

Take {A;B} and add {A;B}+{A;B+1}+{A;B+2}+{A;B+3} branches back up to {A;B} structure 

So that {0;0} branch of final result has {0;0+1+2+3) branches added together

{0;1} has {0;1+2+3+4} and so on