Many conjectures about primes seem to revolve around the idea of "primes are random". So I thought about how this "randomness" may be formally defined, and came up with the following outline:
Describe an algorithm that generates a random sequence "similar" to the primes. A simple example would be Cramer's random model, which selects each integer $n>1$ independently with probability $\frac{1}{\log n}$, but such a sequence may not be "similar" enough to the primes, as it does not accurately describe the distribution of primes mod $n$.
Describe a way to build statements about some sequence $\{a_n\}$ of positive integers. An example may be to build statements using only equality, addition, the universal and existential quantifiers, and taking a term from $\{a_n\}$ (this seems similar to Presburger arithmetic).
Show that, for any statement built from step 2, if it hold with probability $1$ for a random sequence generated from step 1, then it must hold for the sequence of primes. In other words, the statements of step 2 cannot distinguish the primes from a random sequence from step 1. This is similar to the definition of algorithmic randomness.
Clearly step 2 must not allow statements involving divisibility, as then it would be possible to construct the primes. But even if we only use addition, it is still possible to state important conjectures such as the Goldbach conjecture ($\forall n\exists x\exists y(a_x+a_y=n+n)$).
Has such a thing been attempted? Could step 3 even be true for any useful choice of steps 1 and 2?