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A283755 Irregular triangular array read by rows: T(n,k) = number of non-isomorphic unlabeled connected graphs with loops on n nodes and with k edges.

%I A283755 #22 Jan 08 2022 03:36:34
%S A283755 1,1,1,1,1,1,3,3,2,1,2,6,11,13,10,5,2,1,3,14,35,61,75,68,49,28,13,5,2,
%T A283755 1,6,33,112,262,463,625,684,620,468,301,170,82,35,14,5,2,1,11,81,347,
%U A283755 1059,2458,4565,7018,9122,10186,9878,8366,6219,4085,2377,1232,582,251,98,37,14,5,2,1,23,204,1085,4091,12014,28779,58162,101315,154484,208321,250120,268649,258994
%N A283755 Irregular triangular array read by rows: T(n,k) = number of non-isomorphic unlabeled connected graphs with loops on n nodes and with k edges.
%C A283755 The range for the subindex k is from n-1 to n(n+1)/2.
%D A283755 E. Palmer and F. Harary, Graphical Enumeration, Academic Press, 1973.
%H A283755 Marko R. Riedel, <a href="http://math.stackexchange.com/questions/2187019/">Number of distinct connected digraphs</a>
%H A283755 Marko Riedel, <a href="/A283755/a283755_3.maple.txt">Maple code for A070166 and A283755.</a>
%F A283755 T(n,k) = A322114(k,n). - _Andrew Howroyd_, Oct 23 2019
%e A283755 First rows are:
%e A283755 1,  1;
%e A283755 1,  1,  1;
%e A283755 1,  3,  3,  2,  1;
%e A283755 2,  6, 11, 13, 10,  5,  2,  1;
%e A283755 3, 14, 35, 61, 75, 68, 49, 28, 13, 5, 2, 1;
%Y A283755 Row sums are A054921.
%Y A283755 Cf. A000666, A070166, A322114.
%K A283755 nonn,tabf
%O A283755 1,7
%A A283755 _Marko Riedel_, Mar 15 2017