#!/usr/bin/perl

use strict; # https://perlmonks.org/?node_id=11137256
use warnings;

my @a = ( 2,2,2,3,3,4,4 );

my @best = (my $count = 1, my $prev = shift @a);

for my $next ( @a )
  {
  $prev == $next or $prev = $next, $count = 0;
  $best[ ++$count ] = $next;
  }

print "highest count is $#best for the number $best[-1]\n";
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Outputs:

highest count is 3 for the number 2
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