Razor - using foreach, insert html every nth item

Not sure if your wanting to increment the Item number (or if @item.Name actually contains the incremented number), but the following code will increment both the class name (a new div every 4th iteration) and the item number.

@{ var t = 0; var i = 1;  }
<div class="tab-@t">  
    @foreach (var item in Model.Items)
    {
        <a>Item @i</a> // this may be just @item.Name?
        if (i % 4 == 0)
        {
            t++;
            @:</div><div class="tab-"@t>
        }
        i++;
    }
</div>