A046091 - OEIS

A046091

Number of connected planar graphs with n edges.

1, 1, 1, 3, 5, 12, 30, 79, 227, 709, 2318, 8049, 29372, 112000, 444855, 1833072, 7806724, 34252145, 154342391, 712231465, 3357126655, 16119421175, 78580665333

(list; graph; refs; listen; history; text; internal format)

OFFSET

0,4

COMMENTS

Inverse Euler transform of A343872. - Andrew Howroyd, May 05 2021

LINKS

Table of n, a(n) for n=0..22.

B. D. McKay and A. Piperno, Practical Graph Isomorphism, II, J. Symbolic Computation, 60 (2014), pp. 94-112.

Eric Weisstein's World of Mathematics, Planar Connected Graph.

EXAMPLE

a(3) = 3 since the three connected graphs with three edges are a path, a triangle and a "Y".

The first difference between this sequence and A002905 is for n=9 edges where we see K_{3,3}, the "utility graph".

PROG

(nauty)

# count graphs for the sequence by number of vertices v, sum over v afterwards

geng -c $v $n:$n | planarg -q | countg -q # Georg Grasegger, Jul 06 2023

CROSSREFS

Row sums of A343873.

Column sums of A049334.

Cf. A002905, A003094, A066951, A291842, A343869, A343872.

Sequence in context: A317580 A066951 A295065 * A002905 A220832 A323270

Adjacent sequences: A046088 A046089 A046090 * A046092 A046093 A046094

KEYWORD

nonn,nice,hard,more

AUTHOR

Brendan McKay

EXTENSIONS

a(11)-a(19) from Martin Fuller using nauty by Brendan McKay, Mar 07 2015

a(20)-a(22) added by Georg Grasegger, Jul 06 2023

STATUS

approved

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