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A137193 Number of n-celled polyhexes with perimeter < 4n+2. 0
0, 0, 1, 2, 10, 46, 215, 1037, 5083, 24918, 122437 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,4

COMMENTS

These are n-cell polyhexes with the perimeter less than the maximum possible one.

If we associate a graph to a polyhex with vertices representing cells and edges representing two cells with a common edge, then this sequence enumerates polyhexes whose corresponding graphs have cycles.

LINKS

Table of n, a(n) for n=1..11.

FORMULA

A000228(n)-A038142(n)

CROSSREFS

Sequence in context: A106709 A204091 A221196 * A006213 A137635 A029706

Adjacent sequences:  A137190 A137191 A137192 * A137194 A137195 A137196

KEYWORD

hard,more,nonn

AUTHOR

Tanya Khovanova, Mar 03 2008

STATUS

approved

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Last modified April 1 05:04 EDT 2020. Contains 333155 sequences. (Running on oeis4.)