or download this
my $statusCaseNumFormula = '=COUNTIF($I$3:$I$1000,$A$';
my $caseNumFormulaEnder = ')';
...
$formula = $statusCaseNumFormula . $caseNumFormulaCounter . $caseN
+umFormulaEnder;
$gray25percentFormat->set_align('right');
$worksheet->write_formula($row,$col, $formula, $gray25percentForma
+t);