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

1, 2, 18, 440, 32404, 7423456, 5473328160, 13430706072192, 113086387825668384, 3345639802029563258880, 353900830082830194441001984, 135600928084762756427776332541952, 190092581374833963606044859875698932736, 982736440685354936080688846774429648871161856

Offset: 1

Author

Jim Snyder-Grant, Jan 30 2022

Keywords

• nonn

Examples

			For n=3, 18 digraph edge-sets (vertex 0 is the single global sink):
  {21,10}
  {20,10}
  {22,21,10}
  {22,20,10}
  {21,12,10}
  {21,11,10}
  {20,12,10}
  {22,21,12,10}
  {22,21,11,10}
  {22,20,12,10}
  {22,20,11,10}
  {21,20,12,10}
  {21,12,11,10}
  {20,11,12,10}
  {22,21,20,12,10}
  {22,21,12,11,10}
  {22,20,12,11,10}
  {22,21,20,12,11,10}.
		

Links

• Jim Snyder-Grant, C code to generate and count digraphs with global sinks
• Eric Weisstein's World of Mathematics, Digraph Sink

Crossrefs

Cf. A350360 (self-loops not allowed).

Programs

C

// See Jim Snyder-Grant C code to generate and count digraphs with global sinks ./gsinks -l

PARI

\\ See PARI link in A350794 for program code.
seq(n)={Vec(InitiallyV(GraphCIData(n,DigraphWithLoopEdges)))} \\ Andrew Howroyd, Jan 30 2022

Extensions

Terms a(8) and beyond from Andrew Howroyd, Jan 30 2022