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A361590 Triangle read by rows: T(n,k) is the number of digraphs on n unlabeled nodes with exactly k strongly connected components of size 1.

%I A361590 #8 Mar 16 2023 19:46:11
%S A361590 1,0,1,1,0,2,5,5,0,6,90,55,42,0,31,5289,2451,974,592,0,302,1071691,
%T A361590 323709,94332,29612,15616,0,5984,712342075,135208025,25734232,6059018,
%U A361590 1650492,795930,0,243668,1585944117738,181427072519,21650983294,3358042412,704602272,174576110,79512478,0,20286025
%N A361590 Triangle read by rows: T(n,k) is the number of digraphs on n unlabeled nodes with exactly k strongly connected components of size 1.
%e A361590 Triangle begins:
%e A361590         1;
%e A361590         0,      1;
%e A361590         1,      0,     2;
%e A361590         5,      5,     0,     6;
%e A361590        90,     55,    42,     0,    31;
%e A361590      5289,   2451,   974,   592,     0, 302;
%e A361590   1071691, 323709, 94332, 29612, 15616,   0, 5984;
%e A361590   ...
%o A361590 (PARI) \\ See PARI link in A350794 for program code.
%o A361590 { my(A=A361590triang(6)); for(n=1, #A, print(A[n])) }
%Y A361590 Column k=0 is A361586.
%Y A361590 Main diagonal is A003087.
%Y A361590 Row sums are A000273.
%Y A361590 The labeled version is A361592.
%Y A361590 Cf. A350794, A361582, A361588.
%K A361590 nonn,tabl
%O A361590 0,6
%A A361590 _Andrew Howroyd_, Mar 16 2023