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A146148
Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in an em 1,1 1,2 2,2 2,3 3,3 in any orientation.
0
1, 1, 1, 3, 5, 7, 25, 61, 137, 491, 1895, 6799, 35271, 188161, 1045823, 6942831, 54475785, 429190219, 4220050567, 45840848045, 555820995851, 7424820570827, 118936859724455, 2001479983540325, 39919686781316217, 873987056828886899
OFFSET
1,4
EXAMPLE
Maximal 8 X 8 example
.0.0.1.0.0.1.1.0
.0.1.1.0.0.0.1.1
.1.1.0.1.1.0.0.1
.0.0.1.0.1.1.0.0
.0.0.1.1.0.1.0.0
.1.0.0.1.1.0.1.1
.1.1.0.0.0.1.1.0
.0.1.1.0.0.1.0.0
CROSSREFS
Sequence in context: A108313 A045966 A374670 * A098475 A131039 A362684
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 27 2008
STATUS
approved