A146140 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 5-point barb 1,1 1,2 2,2 2,3 3,2 in any orientation.

1, 1, 1, 1, 1, 1, 5, 13, 25, 57, 197, 913, 4565, 21033, 117411, 799889, 6782571, 62778947, 652383615, 7631737235, 109519353841, 1777185991253, 33840206146839, 713322877970345, 17898267949061373, 507994433535644661

Offset

1,7

Links

Table of n, a(n) for n=1..26.

Example

Maximal 8 X 8 example
.0.0.0.0.1.0.0.0
.0.0.0.0.1.1.0.0
.0.0.0.1.1.0.1.0
.0.0.1.0.0.1.1.1
.1.1.1.0.0.1.0.0
.0.1.0.1.1.0.0.0
.0.0.1.1.0.0.0.0
.0.0.0.1.0.0.0.0

Crossrefs

Sequence in context: A249513 A147090 A097117 * A146283 A026373 A066885

Adjacent sequences: A146137 A146138 A146139 * A146141 A146142 A146143

Keyword

nonn

Author

R. H. Hardin, Oct 27 2008

Status

approved