Sequence of numbers with infinite number of primes If I have an infinite sequence of positive integers with infinite number of primes and if I have an infinite number of distinct sequences with such properties may I claim that there is an infinite number of primes on $n$ -th position,where $n$ is arbitrary number ?
Maybe this question is somehow related with probability but I don't see that relation.
 A: No.  Suppose the first sequence is just the sequence of all primes:
$$
2,3,5,7,11,13,17,19,23,29,\ldots
$$
and the second is the same except that $4$ appears where $2$ appeared before:
$$
4,3,5,7,11,13,17,19,23,29,\ldots
$$
and the third sequence is the same except that $6$ appears where $2$ appeared in the first one:
$$
6,3,5,7,11,13,17,19,23,29,\ldots
$$
the the fourth one is the same except that $8$ appears in the first position, and so on.
Then it is not true that there are infinitely many primes in the first position.
A: No, because I could take any collection of sequences you gave me and I could add $n$ zeros to the beginning of each and I'd still have an infinite number of distinct sequences with an infinite number of primes each.  Yet, there would be 0 primes in the 1st through $n$th position.
A: That conclusion doesn't follow from what you're given. For example, let the $k$th sequence be $\{2k+1,2k+2,2k+3,\dots\}$ (just all the integers in a row, starting from $2k+1$). Then each sequence contains infinitely many primes, but none of the sequences has a prime in the $4$th position (or indeed, in the $n$th position for any even number $n\ge4$).
A: If I understand what you are saying, the answer would be "no".
For any subset $S$ of $\mathbb{N}$ that has infinite complement, there are uncountably many sequences of natural numbers that have no primes at all in any position corresponding to $S$ and have an infinite number of primes in positions corresponding to the complement. In particular, specify any collection of positions that has infinite complement, and there are uncountably many sequences, each of which has infinitely many prime terms, but that have no primes at all in the specified collection of positions. 
You can even take an increasing sequence of subsets $S$ so that no specific position will have more than finitely many primes in them: start as Michael Hardy's answer. Then replace the first entry with a nonprime. Then replace the second entry with a nonprime. Then replace the third entry with a nonprime. Etc. Then position $n$ will have primes only in the first $n$ sequences of your list, so no position has primes infinitely often.
