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A145810 Number of islands of ones fitting in an n X n array symmetric under horizontal reflection with all ones connected only either three adjacent vertically or three adjacent horizontally. 0
0, 0, 2, 2, 4, 4, 8, 8, 14, 12, 20, 20, 27, 28, 38, 36, 47, 48 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,3

LINKS

Table of n, a(n) for n=1..18.

EXAMPLE

8 X 8 example with 8 islands

.1.1.1.0.0.1.1.1

.0.0.0.0.0.0.0.0

.0.0.0.0.0.0.0.0

.1.1.1.0.0.1.1.1

.0.0.0.0.0.0.0.0

.1.0.1.0.0.1.0.1

.1.0.1.0.0.1.0.1

.1.0.1.0.0.1.0.1

CROSSREFS

Sequence in context: A108747 A116931 A206558 * A172148 A205478 A262966

Adjacent sequences:  A145807 A145808 A145809 * A145811 A145812 A145813

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 20 2008

STATUS

approved

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Last modified October 20 12:34 EDT 2018. Contains 316379 sequences. (Running on oeis4.)