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A173403
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Inverse binomial transform of A002416.
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5
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1, 1, 13, 469, 63577, 33231721, 68519123173, 562469619451069, 18442242396353040817, 2417685638793025070212561, 1267626422541873052658376446653, 2658442047546208031914776455678477989, 22300713297142388711251601783864453690641417
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OFFSET
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0,3
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COMMENTS
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a(n) is the number of n X n matrices of 0's and 1's with the property that there is no index k such that both the k-th column and the k-th row consist of all zeros.
a(n) is the number of binary relations on n labeled vertices with no vertex of indegree and outdegree = 0. - Geoffrey Critzer, Oct 02 2012
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REFERENCES
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E. A. Bender and S. G. Williamson, Foundations of Combinatorics with Applications, Dover, 2005, exercise 4.1.6.
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LINKS
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FORMULA
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a(n) = Sum_{k=0..n} (-1)^k*binomial(n,k)*2^((n-k)^2).
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MAPLE
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N:=8: seq( sum(binomial(n, i)*2^((n-i)^2)*(-1)^(i), i=0..n), n=0..N);
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MATHEMATICA
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Table[Sum[(-1)^k Binomial[n, k] 2^(n-k)^2, {k, 0, n}], {n, 0, 20}] (* Geoffrey Critzer, Oct 02 2012 *)
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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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