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A145809 Number of islands of ones fitting in an n X n array with all ones connected only either three adjacent vertically or three adjacent horizontally. 0
0, 0, 2, 2, 4, 6, 8, 10, 14, 15, 20, 24 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..12.

EXAMPLE

8 X 8 example with 10 islands

.0.1.1.1.0.1.1.1

.1.0.0.0.0.0.0.0

.1.0.0.0.0.1.1.1

.1.0.1.1.1.0.0.0

.0.0.0.0.0.1.1.1

.1.0.1.1.1.0.0.0

.1.0.0.0.0.1.1.1

.1.0.1.1.1.0.0.0

CROSSREFS

Sequence in context: A202102 A118303 A145817 * A116859 A179999 A286736

Adjacent sequences:  A145806 A145807 A145808 * A145810 A145811 A145812

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 20 2008

STATUS

approved

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Last modified February 18 05:48 EST 2018. Contains 299298 sequences. (Running on oeis4.)