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I have a list $L$ of ordered pairs $(n,m)$ where $n$ and $m$ are integers. I would like to know which elements $(n,m)$ in $L$ satisfy the property that $\gcd(n+i,m+j) \neq 1$ for $i =-1,0,1$ and $j =-1,0,1.$ For example the point $(55,21)$ has this property since $[(55+i,21+j) ] = [(54,20),(54,21),(54,22),(55,20),(55,21),(55,22),(56,20),(56,21),(56,22)].$ I have tried the following : for (n,m) in L: for i in range(-1,2): for j in range(-1,2): if gcd(n+i,m+j)!=1: print(n,m) which returns any point with $gcd =1$ which is not what I want. Thanks very much for your help!