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A145817
Number of islands of ones fitting in an n X n array symmetric under 180 degree rotation with all ones connected only either three adjacent vertically or three adjacent horizontally.
0
0, 0, 2, 2, 4, 6, 8, 10, 14, 14, 19, 24, 26, 30, 38
OFFSET
1,3
EXAMPLE
8 X 8 example with 10 islands
.1.0.1.1.1.0.0.0
.1.0.0.0.0.1.1.1
.1.0.1.1.1.0.0.0
.0.0.0.0.0.1.1.1
.1.1.1.0.0.0.0.0
.0.0.0.1.1.1.0.1
.1.1.1.0.0.0.0.1
.0.0.0.1.1.1.0.1
CROSSREFS
Sequence in context: A202102 A300576 A118303 * A145809 A309711 A116859
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 20 2008
STATUS
approved