Perhaps premature optimization, but I'd recommend switching your tests around so that you only look for matches of numbers you care about:-

if ($data[$i] =~ m/^(?:81|82)$/ && $data[$i] eq $data[$i+1]) {
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(Note the addition of anchors in the regex so you don't accidentally match a pair of, say, 181s.)

And if the number of numbers you're trying to matches is likely to grow or change often, it may be easier using a hash instead of a regex:-

my %wanted = map { $_, 1 } qw(
    81
    82
);

# ...

for my $i (0 .. ($#data - 1)) {
    if (exists $wanted{$data[$i]} && $data[$i] eq $data[$i+1]) {
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