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A146147
Number of n X n binary arrays symmetric about main diagonal with all ones connected only in an em 1,1 1,2 2,2 2,3 3,3 in any orientation.
0
1, 1, 3, 7, 17, 57, 295, 1823, 12191, 109351, 1406131, 21111023, 390067193, 9744306045, 307351023911, 11997000829617, 605954154512379, 39113863932012429, 3182367148757620917, 330528821610534812877
OFFSET
1,3
EXAMPLE
Maximal 8 X 8 example
.0.1.1.0.1.1.0.1
.1.1.0.1.1.0.1.1
.1.0.0.1.0.1.1.0
.0.1.1.0.0.0.0.0
.1.1.0.0.0.1.1.0
.1.0.1.0.1.1.0.1
.0.1.1.0.1.0.1.1
.1.1.0.0.0.1.1.0
CROSSREFS
Sequence in context: A096358 A359174 A260349 * A153758 A079634 A357784
KEYWORD
nonn
AUTHOR
R. H. Hardin, Oct 27 2008
STATUS
approved