What is the largest integer such that there is exactly one way to express as a product of even positive integers and with
None of and is divisible by and
.
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For there to be only one way to express N as a product of p and q through the conditions, N must be the product of 4 and a prime, k .
This means that N = 2 2 ∗ k .
There is only one pair of integers p and q that will suffice here, and they are 2 and 2 k .
k must be the largest prime ≤ ⌊ 4 2 0 1 7 ⌋ = 5 0 4 .
Thus k is 503, and N is 4 k = 4 ∗ 5 0 3 = 2 0 1 2 .