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A285052
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Number of idempotent equivalence classes for multiplication in Zn.
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2
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1, 4, 4, 4, 4, 16, 4, 4, 4, 16, 4, 16, 4, 16, 16, 4, 4, 16, 4, 16, 16, 16, 4, 16, 4, 16, 4, 16, 4, 64, 4, 4, 16, 16, 16, 16, 4, 16, 16, 16, 4, 64, 4, 16, 16, 16, 4, 16, 4, 16, 16, 16, 4, 16, 16, 16, 16, 16, 4, 64, 4, 16, 16, 4, 16, 64, 4, 16, 16, 64, 4, 16, 4, 16, 16, 16, 16, 64, 4, 16, 4, 16, 4, 64, 16, 16, 16, 16, 4, 64, 16
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OFFSET
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1,2
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COMMENTS
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Consider triples (a,b,c) over Zn where a*b=c. Map each of the three elements to its idempotent under self multiplication, (g^i) * (g^i) = (g^i). Count the distinct triples.
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LINKS
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FORMULA
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EXAMPLE
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For n=6: [(0,0,0),(0,1,0),(0,4,0),(0,3,0),(1,0,0),(1,1,1),(1,4,4),(1,3,3),(4,0,0),(4,1,4),(4,4,4),(4,3,0),(3,0,0),(3,1,3),(3,4,0),(3,3,3)], so a(6) = 16.
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CROSSREFS
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KEYWORD
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nonn
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AUTHOR
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STATUS
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approved
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