I hoped this article would explain how many logical qubits are required to run the fully general Shor's algorithm (without precompilation cheats and such) to factor e.g. the product of two 6-bit primes, but it seems more geared to advertising a quantum circuit controller that this company makes:

> Controlling 1015 qubits requires thousands of synchronized analog control channels attached to a powerful orchestration brain able to handle thousands of simultaneous operations. Adopting a modular approach, QM has tackled this challenge by creating OPX1000, the most advanced and highest-scale quantum controller in industry.

The article suggests that only 5 logical qubits are needed to factor the product of two 3-bit primes, but how does one arrive at that number? Shor's algorithm requires performing a multiplication of two k-bit numbers, which would seem to require more than 2k-1 bits. So what do these 5 qubits correspond to exactly in Shor's algorithm?