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A351052 Number of unlabeled digraphs with n nodes containing a global sink (or source), self-loops allowed. 0
1, 2, 18, 440, 32404, 7423456, 5473328160, 13430706072192, 113086387825668384, 3345639802029563258880, 353900830082830194441001984, 135600928084762756427776332541952, 190092581374833963606044859875698932736, 982736440685354936080688846774429648871161856 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

LINKS

Table of n, a(n) for n=1..14.

Jim Snyder-Grant, C code to generate and count digraphs with global sinks

Eric Weisstein's World of Mathematics, Digraph Sink

EXAMPLE

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}.

PROG

(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

CROSSREFS

Cf. A350360 (self-loops not allowed).

Sequence in context: A201732 A260656 A141074 * A082402 A208055 A306655

Adjacent sequences:  A351049 A351050 A351051 * A351053 A351054 A351055

KEYWORD

nonn

AUTHOR

Jim Snyder-Grant, Jan 30 2022

EXTENSIONS

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

STATUS

approved

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Last modified August 9 12:53 EDT 2022. Contains 356026 sequences. (Running on oeis4.)