Aha! Thanks for the reply.

And no, the factor 3 was a mistake from my side. CAS automically inserts a number (1,2,3,4...), equivalent to the Maple-system with:

Pi _Z1~, where it systematises the arbitrary integer in numbers (for instance: Z1, Z2 etc.). 
Of course it doesn't mean it's a factor 3.. my bad :p