# Renaming iteratively product of variables

It is a rather easy problem but I don't manage to solve it.

Expand[(a[1] x + a[2] y + a[3] z) (b[1] x + b[2] y + b[3] z) (c[1] x +
c[2] y + c[3] z)]


The problem is that is gives me product of a[i] b[j] c[k] as coefficients and I would like to have instead something like d[ijk].

Example :

a[1]b[3]c[2] xyz -> d[132] xyz


Attempt :

equa = Expand[(a[1] x + a[2] y + a[3] z) (b[1] x + b[2] y +
b[3] z) (c[1] x + c[2] y + c[3] z)]
For[i = 1, i <= 3, i++,
For [j = 1, j <= 3, j++,
For[k = 1, k <= 3, k++,
equa = equa /. {a[i] b[j] c[k] -> d[i j k]}
]]]


but ijk in d[i j k] are multiplied.

exp = Expand[(a[1] x + a[2] y + a[3] z) (b[1] x + b[2] y +