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A164099 Number of planar graphs with n nodes and chromatic number 2. 1
1, 2, 6, 12, 33, 83, 273, 937, 3983, 18871, 103697, 628245, 4161652, 29372754, 218035754 (list; graph; refs; listen; history; text; internal format)
OFFSET

2,2

LINKS

Table of n, a(n) for n=2..16.

FORMULA

(Euler transform of A243321) - 1. - Falk Hüffner, May 10 2019

CROSSREFS

Sequence in context: A217447 A057579 A096610 * A088808 A076278 A221989

Adjacent sequences:  A164096 A164097 A164098 * A164100 A164101 A164102

KEYWORD

nonn

AUTHOR

Keith Briggs, Aug 10 2009

EXTENSIONS

Added term 18871 (for n=11), Keith Briggs, Aug 25 2009

a(12)-a(16) from formula by Falk Hüffner, May 10 2019

STATUS

approved

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Last modified October 20 22:22 EDT 2021. Contains 348119 sequences. (Running on oeis4.)