@tect1=(1,5,6,8,16,20);
@tect2=(1,7,10,12,13,14,15,18,19,22,23,24,46);
@tect3=(1,2,3,9,10,11,17,21,24,39,46);
@tectlist=(\@tect1, \@tect2, \@tect3);
$variable=19; #as an example

for $i (0..$#tectlist) {
 if (grep (/$variable/, @{$tectlist[$i]})){
  print" List";
  $listnumber=$i+1;
  print" $listnumber";
  print " contains $variable.\n";
  }
 }