How to use VBA to put spaces in Concat

Hey,
I'm trying to put spaces between each number but can't figure out how to put " " into formula I tried "&"" ""&" but it doesn't work for me.

While Cells(id + 1, x) <> ""
a = a & ";" & " " & ";" & Cells(id + 1, x).Formula
x = x + 1
Wend

a = Replace(a, ".", ",")

Cells(id + 1, 3).FormulaLocal = "=concat(" & a & ")"