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1, 2, 4, 10, 41, 343, 6327, 249995, 20536020, 3445474030, 1169394086932, 798731069436512, 1094825607339329108, 3006942191342795594938, 16533858553282474307626008, 181924651566316766693192987410
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OFFSET
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0,2
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COMMENTS
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Partial sums of number of acyclic digraphs with n unlabeled nodes; equivalently partial sums of the number of equivalence classes of n X n real (0,1)-matrices with all eigenvalues positive, up to conjugation by permutations. The subsequence of primes in this partial sum begins: 2, 41, no more through a(18).
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FORMULA
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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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