Formula For Linked Worksheet Last Row

I am trying to find the last row of worksheet "A", return the value, then in Worksheet "B", reference Worksheet "A" Column J - last row. It gives me an error for the formula. I don't know if I am close to the solution, or way off. Here is my code:

Dim LastRow As Long
Sheets("NICMap31 Data").Select 'goes to worksheet A
Range("A1").Select
LastRow = Cells(Rows.Count, "A").End(xlUp).Offset(1).Row 'finds the last row of worksheet A
Sheets("NIC MAP Data Table").Select 'returns to worksheet B
Range("C7").Select
ActiveCell.formula = "='NICMap31 Data'!(J & LastRow - 1)" 'link to worksheet A with this formula.