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A057277 Triangle T(n,k) of number of digraphs with a source on n unlabeled nodes with k arcs, k=0,1,..,n*(n-1). 2

%I

%S 1,0,1,1,0,0,2,4,4,1,1,0,0,0,4,16,34,46,38,27,13,5,1,1,0,0,0,0,9,56,

%T 229,573,1058,1448,1653,1487,1153,707,379,154,61,16,5,1,1

%N Triangle T(n,k) of number of digraphs with a source on n unlabeled nodes with k arcs, k=0,1,..,n*(n-1).

%e [1], [0, 1, 1], [0, 0, 2, 4, 4, 1, 1], [0, 0, 0, 4, 16, 34, 46, 38, 27, 13, 5, 1, 1], ....

%e Number of digraphs with a source on 3 unlabeled nodes is 12=2+4+4+1+1.

%Y Row sums give A051421. Cf. A057270-A057276, A057278-A057279.

%K more,nonn,tabf

%O 1,7

%A _Vladeta Jovovic_, Goran Kilibard, Sep 14 2000

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Last modified March 25 08:15 EDT 2019. Contains 321469 sequences. (Running on oeis4.)