my @list = ( 41888, 41889, 41890, 41892, 41895 );

my @missing = do {
    my %missing;
    undef @missing{ $list[ 0 ] .. $list[ -1 ] };
    delete @missing{ @list };
    keys %missing;
};

##</code><code>##

my @missing;
{
    my $i = 0;
    for ( $list[ 0 ] .. $list[ -1 ] ) {
        ++$i, next if $_ == $list[ $i ];
        push @missing, $_;
    }
}

##</code><code>##

my @missing = do {
    my $i = 0;
    grep { $_ == $list[ $i ] ? ++$i && 0 : 1 } $list[ 0 ] .. $list[ -1 ];
};