my %oc;
for (0 .. $#sequence) {
  $oc{$sequence[$_]}[0] =
    ($oc{$sequence[$_]}[0]+$numbers[$_])/(++$oc{$sequence[$_]}[1]);
}
foreach my $seq (keys %oc) {
  print "The average for $seq is ".$oc{$seq}[0].$/;
}