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A213690
Half the number of (n+1)X(n+1) symmetric 0..1 arrays with no 2X2 subblock summing to 2.
1
3, 13, 70, 529, 5148, 68798, 1220409, 29377751, 949700962, 41536397680, 2450653487731, 195553849371916, 21091722699002539, 3077853629320011499, 607688763160596614184, 162407853243770174812161
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OFFSET
1,1
COMMENTS
Column 1 of
A213697
LINKS
R. H. Hardin,
Table of n, a(n) for n = 1..18
EXAMPLE
Some solutions for n=4
..1..0..0..0..0....0..0..1..0..1....0..1..0..1..0....1..1..0..1..1
..0..0..1..0..1....0..1..1..1..1....1..1..1..1..1....1..1..1..1..1
..0..1..1..1..1....1..1..0..1..0....0..1..1..1..1....0..1..1..1..0
..0..0..1..1..1....0..1..1..1..1....1..1..1..0..1....1..1..1..0..0
..0..1..1..1..1....1..1..0..1..0....0..1..1..1..1....1..1..0..0..0
CROSSREFS
Sequence in context:
A024337
A001495
A284217
*
A227117
A277922
A182189
Adjacent sequences:
A213687
A213688
A213689
*
A213691
A213692
A213693
KEYWORD
nonn
AUTHOR
R. H. Hardin
, Jun 18 2012
STATUS
approved
