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A122672 Number of primitive coronoid systems with n hexagons. 1
1, 1, 3, 2, 11, 12, 40, 68, 192, 395, 1061, 2432, 6318, 15417, 39660, 99550, 256388, 654003, 1689973, 4355457, 11305165, 29347706, 76527893 (list; graph; refs; listen; history; text; internal format)
OFFSET

8,3

LINKS

Table of n, a(n) for n=8..30.

S. J. Cyvin et al., The simplest coronoids: hollow hexagons, Struct. Chem., 2 (1991), 555-566.

Johan Nilsson, Illustrations for initial terms

CROSSREFS

Sequence in context: A159610 A074246 A134426 * A194608 A297870 A052973

Adjacent sequences:  A122669 A122670 A122671 * A122673 A122674 A122675

KEYWORD

nonn

AUTHOR

N. J. A. Sloane, Sep 23 2006

EXTENSIONS

a(15)-a(30) from Johan Nilsson, Aug 12 2015

STATUS

approved

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Last modified March 21 01:18 EDT 2019. Contains 321356 sequences. (Running on oeis4.)