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Scraped a couple bytes off.

edited Jan 3, 2018 at 16:50

Ruby, 97₉₇ 95 bytes

->n{c=!r=[1,1] (2...n).map{|i|c|=1>n%i r=[0[n]&r=[0,*r,0].each_cons(2).map{|a,b|a+b}}.flatten&[n]==[]&&c&[[n]]==[]&&c}

I'm sure it can be made smallerScraped a couple bytes off.

->n{c=!r=[1,1] (2...n).map{|i|c|=1>n%i r=[0,*r,0].each_cons(2).map{|a,b|a+b}}.flatten&[n]==[]&&c}

I'm sure it can be made smaller.

->n{c=!r=[1,1] (2...n).map{|i|c|=1>n%i [n]&r=[0,*r,0].each_cons(2).map{|a,b|a+b}}&[[n]]==[]&&c}

Scraped a couple bytes off.

answered Jan 2, 2018 at 23:42

->n{c=!r=[1,1] (2...n).map{|i|c|=1>n%i r=[0,*r,0].each_cons(2).map{|a,b|a+b}}.flatten&[n]==[]&&c}

I'm sure it can be made smaller.