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%I #10 Nov 27 2018 04:45:23
%S 2,10,752,179228736,10074382205972351614976
%N Number of unlabeled general directed hypergraphs of order n.
%H J. Qian, <a href="http://www.combinatorics.org/ojs/index.php/eljc/article/view/v20i1p46">Enumeration of unlabeled directed hypergraphs</a>, Electronic Journal of Combinatorics, 20(1) (2013), #P46.
%e The 10 non-isomorphic directed hypergraphs of order 2 are as follows (these are their arc sets): {<1,0>, <2,0>}, {<1, {2}>, <2, {1}>}, {<1, {2}>, <1,0>, <2, {1}>, <2,0>}, {<1, {2}>}, {<1, {2}>, <1,0>}, {<1, {2}>, <1,0>, <2, {1}>}, {<1,0>}, {<1, {2}>, <2,0>}, {<1, {2}>, <1,0>, <2,0>}, 0.
%Y Cf. A000273, A222421.
%K nonn,more
%O 1,1
%A _N. J. A. Sloane_, Mar 01 2013