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A146060
Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 2X3 U in any orientation.
0
1, 1, 1, 1, 1, 5, 15, 27, 53, 153, 487, 1719, 7415, 32545, 166197, 903303, 5463687, 37085195, 288519629, 2455679981, 24371430209, 259645240127, 3154594586943, 41721327840785, 629945561496623
OFFSET
1,6
EXAMPLE
Maximal 8 X 8 example
.1.1.0.0.0.1.0.1
.0.1.0.0.0.1.1.1
.1.1.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.1.1
.1.1.1.0.0.0.1.0
.1.0.1.0.0.0.1.1
CROSSREFS
Sequence in context: A339567 A067533 A110343 * A076843 A285406 A129393
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 26 2008
STATUS
approved