<?php
$enderecos = array(array('cep' => '00000-00', 'rua' => 'Rua XXXX'), array('cep' => '11111-111', 'rua' => 'Rua YYYY'));
$i = 1;
$c = 0;
foreach ($enderecos as $endereco) {
$j = $i + 1;
?>
<input type="text" name="endereco[<?php echo $c;?>][cep]" value="<?php echo $endereco['cep']; ?>" tabindex="<?php echo $i; ?>">
<input type="text" name="endereco[<?php echo $c;?>][rua]" value="<?php echo $endereco['rua']; ?>" tabindex="<?php echo $j; ?>">
<?php
$i+=2; // incrementar 2
$c++;
}
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