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A304884
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Size of the largest subset of the cyclic group of order n which does not contain a nontrivial 3-term arithmetic progression.
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0
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1, 2, 2, 2, 2, 2, 3, 3, 4, 4, 4, 4, 4, 4, 4, 4, 5, 5, 6, 5, 6, 6, 6, 6, 7, 7, 8, 8, 8, 8, 8, 8, 8, 8, 9, 8, 10, 8, 10, 9, 9, 9, 9, 9, 10, 10, 10, 10, 10, 10, 11, 12, 11, 11, 11, 11, 12, 11, 12, 12, 13, 12, 13, 13, 14, 13, 13, 13, 14, 14, 14, 14, 14, 14, 14, 14, 14, 14, 15
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OFFSET
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1,2
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COMMENTS
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Each term is at most the corresponding term of A003002.
Arithmetic progressions are trivial if they are of the form x,x,x.
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LINKS
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EXAMPLE
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For n=10, the integers (mod 10) have sets with four elements like {1,2,4,5} which contain no arithmetic progressions with 3 elements, but no such sets with five elements. For example, {1,2,4,5,8} has the progression 2,8,4, and {1,2,4,5,9} has the progression 4,9,4. Since four is the most elements possible, a(10) = 4. - Michael B. Porter, May 26 2018
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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EXTENSIONS
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STATUS
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approved
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