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A185178
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Number of different values of the permanent of an n X n (0,1)-matrix with exactly three 1's in each row and each column.
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4
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OFFSET
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3,3
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COMMENTS
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The values a(n) are unknown for n>=9.
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REFERENCES
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V. I. Bolshakov, On spectrum of permanent on Lambda_n^k, Proc. of Seminar on Discrete Math. and Appl., Moscow State Univ. (1986), 65-73 (in Russian).
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LINKS
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CROSSREFS
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KEYWORD
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nonn,bref,hard,more
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AUTHOR
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STATUS
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approved
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