BEGIN{
       FS="\t"
   }
{
    gsub(/[0-9]/,"",$1) # Delete numbers from formula
    gsub(/\|/," ",$1) # Replace | by space
    e=split($1,elem," ") # Create an array of elements
    for (i=1;i<=e;i++){
	num_comp[elem[i]][$1]+=$2  # increase the number of compounds of the combination for each element
	tot_comp[elem[i]]+=$2 # total number of compounds of each element
	comb[elem[i]][$1]++
    }
}
END{
    PROCINFO["sorted_in"]="@val_num_desc" # Loop arrays in descendent order of value.
    for (e in tot_comp){
	el++
	count=0
	expected=0
	for (c in num_comp[e]) { # Loop over motifs of each element
	    expected+=++count*num_comp[e][c]/tot_comp[e]
	}
	print el,e,expected/length(comb[e]),tot_comp[e],length(comb[e]) # Print expected values
    }
}