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A091442
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Table (by antidiagonals) of permutations of two types of objects such that each cycle contains at least one object of each type. Each type of object is unlabeled.
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0
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1, 1, 1, 1, 3, 1, 1, 3, 3, 1, 1, 5, 8, 5, 1, 1, 5, 11, 11, 5, 1, 1, 7, 17, 26, 17, 7, 1, 1, 7, 24, 40, 40, 24, 7, 1, 1, 9, 31, 66, 85, 66, 31, 9, 1, 1, 9, 39, 95, 146, 146, 95, 39, 9, 1, 1, 11, 50, 139, 245, 304, 245, 139, 50, 11, 1, 1, 11, 59, 183, 379, 538, 538, 379, 183, 59, 11
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OFFSET
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1,5
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REFERENCES
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F. Bergeron, G. Labelle and P. Leroux, Combinatorial Species and Tree-Like Structures, Cambridge, 1998, p. 114 (2.4.42).
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LINKS
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FORMULA
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G.f.: A(x, y) = Product_{k>=1} (1 - x^n)*(1 - y^n)/(1 - x^n - y^n).
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EXAMPLE
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1, 1, 1, 1, 1, ...
1, 3, 3, 5, 5, ...
1, 3, 8, 11, 17, ...
1, 5, 11, 26, 40, ...
1, 5, 17, 40, 85, ...
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CROSSREFS
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KEYWORD
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AUTHOR
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STATUS
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approved
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