A215620 - OEIS

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A215620

Numbers of apex graphs (graphs which become or remain planar upon the removal of a single vertex) on n vertices.

2

1, 2, 4, 11, 34, 155, 1026, 11666, 226916, 6810525

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

OFFSET

1,2

COMMENTS

Trivially includes planar graphs.

LINKS

Table of n, a(n) for n=1..10.

Eric Weisstein's World of Mathematics, Apex Graph

CROSSREFS

Cf. A215621 (nonplanar apex graphs).

Cf. A076317 (number of 5-colorable simple graphs on n nodes).

Sequence in context: A217043 A249696 A156809 * A076317 A076318 A046750

Adjacent sequences: A215617 A215618 A215619 * A215621 A215622 A215623

KEYWORD

nonn,more

AUTHOR

Eric W. Weisstein, Aug 17 2012

EXTENSIONS

a(10) from Eric W. Weisstein, Aug 20 2012

STATUS

approved