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A255440
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Number of ordered pairs of permutation functions on n elements satisfying f(g(g(g(x)))) = g(g(g(f(x)))).
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1
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1, 1, 4, 24, 288, 3240, 74160, 1970640, 55762560, 2271628800, 118676275200, 5949399456000, 389282684313600, 31351069535385600, 2431871996666112000, 227068393053325824000, 25547764411931553792000, 2795442523571128983552000, 350437557048098924371968000
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OFFSET
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0,3
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COMMENTS
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See A239841 for more information and a proof that a(n) is a multiple of n!.
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LINKS
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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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