|
%I #9 Jan 09 2022 13:10:19
%S 1,0,1,0,0,3,0,0,1,8,0,0,0,9,27,0,0,0,6,54,91,0,0,0,1,79,320,350,0,0,
%T 0,0,63,732,1788,1376,0,0,0,0,33,1136,6012,9933,5743,0,0,0,0,10,1281,
%U 14378,45225,54502,24635,0,0,0,0,1,1056,26529,151848,322736,298250,108968
%N Triangle read by rows: T(n,k) is the number of unlabeled weakly connected acyclic digraphs with n arcs and k vertices, n >= 0, k = 1..n+1.
%H Andrew Howroyd, <a href="/A350450/b350450.txt">Table of n, a(n) for n = 0..860</a> (rows 0..40)
%e Triangle begins:
%e 1;
%e 0, 1;
%e 0, 0, 3;
%e 0, 0, 1, 8;
%e 0, 0, 0, 9, 27;
%e 0, 0, 0, 6, 54, 91;
%e 0, 0, 0, 1, 79, 320, 350;
%e 0, 0, 0, 0, 63, 732, 1788, 1376;
%e 0, 0, 0, 0, 33, 1136, 6012, 9933, 5743;
%e ...
%o (PARI) \\ See PARI link in A122078 for program code.
%o { my(T=WeakAcyclicDigraphsTr(10)); for(n=1, #T, print(T[n])); }
%Y Main diagonal is A000238.
%Y Row sums are A350451.
%Y Column sums are A101228.
%Y Cf. A122078, A350449 (transpose).
%K nonn,tabl
%O 0,6
%A _Andrew Howroyd_, Dec 31 2021
|
