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A003026 Number of n-node acyclic digraphs with 2 out-points.
(Formerly M4666)
5
1, 9, 198, 10710, 1384335, 416990763, 286992935964, 444374705175516, 1528973599758889005, 11573608032229769067465, 191141381932394665770442818, 6839625961762363728765713227698 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

REFERENCES

R. W. Robinson, Counting labeled acyclic digraphs, pp. 239-273 of F. Harary, editor, New Directions in the Theory of Graphs. Academic Press, NY, 1973.

N. J. A. Sloane and Simon Plouffe, The Encyclopedia of Integer Sequences, Academic Press, 1995 (includes this sequence).

LINKS

Table of n, a(n) for n=2..13.

CROSSREFS

Cf. A058876, A003025.

Sequence in context: A019566 A338226 A157563 * A157594 A232276 A196910

Adjacent sequences:  A003023 A003024 A003025 * A003027 A003028 A003029

KEYWORD

nonn

AUTHOR

N. J. A. Sloane.

EXTENSIONS

More terms from Vladeta Jovovic, Apr 10 2001

STATUS

approved

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Last modified July 31 23:29 EDT 2021. Contains 346377 sequences. (Running on oeis4.)