Using this code

Sub Insertformula ()
For Check = 4 To 40000 Step 2
If Cells(Check, "b") < "" Then Cells(Check, "b") =
"=IF(OR(I5="",J5=""),"",NETWORKDAYS(I5,J5,Holidays !A$1:A$39)-1)"
Next Check
End Sub

My objective is to put this formula

=IF(OR(I5="",J5=""),"",NETWORKDAYS(I5,J5,Holidays! A$1:A$39)-1)

Into every even cell in Column B with data below it. However if you tried
the macro you would see it does not work. If I could get any help thank you.