Wednesday, December 16, 2015

"Good" subsets of natural numbers


We define a subset A of positive integers as "Good" if it's possible to write it's members as $a_1$, $a_2$, $a_3$, $\cdots$ so that GCD of any two consecutive numbers $a_i$ and $a_{i+1}$ is greater than $1$. Verify and prove "Goodness" of the following two sets:





  1. Set of positive integers greater than $1$

  2. Set of squares greater than $1$




How to solve this problem?

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