A146034 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 3X3 el 1,1 1,2 1,3 2,3 3,3 in any orientation.

1, 1, 1, 3, 3, 7, 15, 43, 83, 271, 633, 3283, 9541, 54293, 204827, 1408893, 6437305, 54681853, 303651861, 3282191633, 22628378377, 297350762879, 2544553561975, 41024771076465, 431789004830701, 8608866149320377, 111456693040140865

Offset

1,4

Links

Table of n, a(n) for n=1..27.

Example

Maximal 8 X 8 example
.0.0.1.0.0.1.1.1
.0.0.1.0.1.0.0.1
.1.1.1.0.1.0.0.1
.0.0.0.0.1.1.1.0
.0.1.1.1.0.0.0.0
.1.0.0.1.0.1.1.1
.1.0.0.1.0.1.0.0
.1.1.1.0.0.1.0.0

Crossrefs

Sequence in context: A004043 A104176 A032294 * A032029 A058571 A058492

Adjacent sequences: A146031 A146032 A146033 * A146035 A146036 A146037

Keyword

nonn

Author

R. H. Hardin, Oct 26 2008

Status

approved