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A146139
Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 5-point barb 1,1 1,2 2,2 2,3 3,2 in any orientation.
0
1, 1, 1, 1, 7, 21, 61, 403, 3415, 36395, 473261, 8291363, 204964495, 6738662861, 291876652529, 16526293766701, 1250870357604441, 127503882340930419, 17331789387120484429, 3122597067315836972733, 746394914944854757141353
OFFSET
1,5
EXAMPLE
Maximal 8 X 8 example
.0.0.1.1.0.1.1.0
.0.0.0.1.1.0.1.1
.1.0.0.1.0.0.1.0
.1.1.1.0.0.0.0.1
.0.1.0.0.0.1.1.1
.1.0.0.0.1.0.1.0
.1.1.1.0.1.1.0.0
.0.1.0.1.1.0.0.0
CROSSREFS
Sequence in context: A001354 A200930 A088656 * A083596 A082541 A005032
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 27 2008
STATUS
approved