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A351052 Number of unlabeled digraphs with n nodes containing a global sink (or source), self-loops allowed.

%I A351052 #20 Aug 18 2025 18:28:52
%S A351052 1,2,18,440,32404,7423456,5473328160,13430706072192,
%T A351052 113086387825668384,3345639802029563258880,
%U A351052 353900830082830194441001984,135600928084762756427776332541952,190092581374833963606044859875698932736,982736440685354936080688846774429648871161856
%N A351052 Number of unlabeled digraphs with n nodes containing a global sink (or source), self-loops allowed.
%H A351052 Jim Snyder-Grant, <a href="https://github.com/jim-snyder-grant/counting-global-sinks">C code to generate and count digraphs with global sinks</a>
%H A351052 Eric Weisstein's World of Mathematics, <a href="https://mathworld.wolfram.com/DigraphSink.html">Digraph Sink</a>
%e A351052 For n=3, 18 digraph edge-sets (vertex 0 is the single global sink):
%e A351052   {21,10}
%e A351052   {20,10}
%e A351052   {22,21,10}
%e A351052   {22,20,10}
%e A351052   {21,12,10}
%e A351052   {21,11,10}
%e A351052   {20,12,10}
%e A351052   {22,21,12,10}
%e A351052   {22,21,11,10}
%e A351052   {22,20,12,10}
%e A351052   {22,20,11,10}
%e A351052   {21,20,12,10}
%e A351052   {21,12,11,10}
%e A351052   {20,11,12,10}
%e A351052   {22,21,20,12,10}
%e A351052   {22,21,12,11,10}
%e A351052   {22,20,12,11,10}
%e A351052   {22,21,20,12,11,10}.
%o A351052 (C) // See Jim Snyder-Grant C code to generate and count digraphs with global sinks ./gsinks -l
%o A351052 (PARI) \\ See PARI link in A350794 for program code.
%o A351052 seq(n)={Vec(InitiallyV(GraphCIData(n,DigraphWithLoopEdges)))} \\ _Andrew Howroyd_, Jan 30 2022
%Y A351052 Cf. A350360 (self-loops not allowed).
%K A351052 nonn
%O A351052 1,2
%A A351052 _Jim Snyder-Grant_, Jan 30 2022
%E A351052 Terms a(8) and beyond from _Andrew Howroyd_, Jan 30 2022