my %hash = ( artistsong1 => { 1 => 1, 3 => 1, 5 => 1 },
             artistsong2 => { 2 => 1, 4 => 1 } );
# to find  for ArtistSong1, does 1 exist?
if($hash{artistsong1}->{1})
{
  print "yes, 1 does exist for artistsong1!\n";
}

##</code><code>##

my %hash = 
( 1 => artistsong1,
  3 => artistsong1,
  5 => artistsong1,
  2 => artistsong2,
  4 => artistsong2,
  6 => artistsong3,
  7 => artistsong3
);
# to find where 1 is?
my $artistsong = $hash{1};