I had not previously heard of Erthenvar but they do a series of dividers, including Fibonacci numbers. Outstanding.
Memory is a strange (and increasingly unreliable) thing. I first suggested primes in a Yahoo Groups poll in Feb 2010 with a fuller explanation a few days later:
"The reason this idea came to mind was a recent piece in The Times referring to a lecture by Marcus du Sautoy at the Royal Society available here entitled The secret mathematicians, it concerned the use of maths in art and starts with a piece by Messiaen, Quartet for the End of Time. It uses rhythms of 17 and 29 beats - as these are prime numbers, a sequence would not repeat (at least until you get to 17*29).
I think La Monte Young used primes too.
The lecture also refers to the Fibonacci series which I think is mentioned in a later post but I haven't got there yet.
Anyway, as I play with long automated noises, I thought prime-based rhythms would be fun.
A prime number is only divisible by one and itself (2, 3, 5, 7, 11, 13, 17 etc).
Three years later (Feb 2013) I posted again in the thread and mentioned the Erthenvar Fibonacci module.
[19th Aug] The Doepfer Primes arrived today and I have just ordered an Erthenvar Fibonacci. I think my new favourite number is 89: a pity it doesn't feature in the lottery.