#! perl -slw
use strict;
use Data::Dump qw[ pp ]; $Data::Dump::WIDTH = 300;

my( @counts, @ns );

for( 1 .. 1e6 ) {
    my @orderedRands = grep{ rand(1) < 0.05 } map{ ($_) x 20 } 1 .. 20;
    while( @orderedRands != 20 ) {
        @orderedRands = grep{ rand(1) < 0.05 } map{ ($_) x 20 } 1 .. 20;
    }
    ++$ns[ @orderedRands ];
    ++$counts[ $_ ] for @orderedRands;
}

pp \@counts, \@ns;

__END__
C:\test>junk62
(
  [undef, 1000652, 999987, 1000022, 999969, 999146, 1000961, 1000568, 1000129, 1000725, 999884, 999509, 999756, 1000538, 999763, 1000708, 1000826, 999799, 998778, 998714, 999566],
  [undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, undef, 1000000],
)