Sorry. I didn't account for 0-based indices! This produces the correct result:

#! perl -slw
use strict;
my @samples = qw[
    4011350000000008
    4011350000000016
    4011350000000024
    4011350000000032
    4011350000000040
    4011350000000057
    4011350000000065
    4011350000000073
    4011350000000081
    4011350000000099
];

sub luhn {
    my $total = 0;
    for my $i ( 0 .. length( $_[0] ) -1 ) {
        my $d = substr( $_[0], $i, 1 );
        unless( $i & 1 ) {
            $d *= 2;
            $d -=9 if $d > 9;
        }
        $total += $d;
    }
    $total *= 9;
    return substr $total, -1
}

for ( @samples ) {
    print "$_ : ", luhn( substr $_, 0, 15  );
}

__END__
C:\test>luhn
4011350000000008 : 8
4011350000000016 : 6
4011350000000024 : 4
4011350000000032 : 2
4011350000000040 : 0
4011350000000057 : 7
4011350000000065 : 5
4011350000000073 : 3
4011350000000081 : 1
4011350000000099 : 9
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