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A145802
Number of islands of ones fitting in an n X n array symmetric under horizontal reflection with all ones connected only either two adjacent vertically or two adjacent horizontally.
0
0, 1, 2, 4, 6, 9, 12, 15, 19, 25, 28, 33, 40, 49, 53, 60, 69, 81, 86, 95
OFFSET
1,3
EXAMPLE
8 X 8 example with 15 islands
.1.0.0.1.1.0.0.1
.1.0.1.0.0.1.0.1
.0.0.1.0.0.1.0.0
.1.1.0.1.1.0.1.1
.0.0.1.0.0.1.0.0
.1.0.1.0.0.1.0.1
.1.0.0.1.1.0.0.1
.0.1.1.0.0.1.1.0
CROSSREFS
Sequence in context: A261222 A130025 A278299 * A076271 A036441 A180107
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 19 2008
STATUS
approved