Sum Over Relatively Prime Indexes = n

[Leroy Quet]

Consider sequence A070963.
In this sequence, for n >= 2,

n = sum{1 <= k < n, GCD(k,n) =1}  a(k) ,

where the sum is over those positive integers, k, which are < n and are 
relatively prime to n.

(The sequence begins: 2, 1, 2, 0, 4, 2, 0, 2, 6, 4, 6, 4,...
The offset is 1.)

Anyhow, is there a direct (nonrecursive) way to easily calculate these 
terms?

Thanks,
Leroy Quet