I am working on a problem and encountered the following problem:(adsbygoogle = window.adsbygoogle || []).push({});

Given a,b element of {1,7,11,13,17,19,23,29} and also given that :

x,y element of N+{0}.

Now I want to *formlulate* the numbers that are _not_ reachable by the equation :

z = ax + by + 30xy

The formula(tion) should tell instantly whether z is reachable or not for any z element N

Any hints or even resolves are highly appreciated.

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# Integers reachable by ax + by + 30xy

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