##Ruby, 47 bytes
Ruby, 47 bytes
->b{!("%b"%(b/2)=~/0/||(2...b).find{|a|b%a<1})}
##Ruby, 47 bytes
->b{!("%b"%(b/2)=~/0/||(2...b).find{|a|b%a<1})}
Ruby, 47 bytes
->b{!("%b"%(b/2)=~/0/||(2...b).find{|a|b%a<1})}
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Visit Stack Exchange##Ruby, 47 bytes
->b{!("%b"%(b/2)=~/0/||(2...b).find{|a|b%a<1})}
##Ruby, 47 bytes
->b{!("%b"%(b/2)=~/0/||(2...b).find{|a|b%a<1})}
->b{!("%b"%(b/2)=~/0/||(2...b).find{|a|b%a<1})}