A145927 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a tee 1,1 1,2 1,3 2,2 in any orientation.

1, 1, 1, 1, 6, 1, 38, 9, 408, 33, 7604, 404, 271731, 7941, 15992426, 262632, 1666574068, 14831415, 309972197784, 1538127410, 100682581657471, 275592188347, 57498326956771300, 87279885007004, 57832081083719379686

Offset

1,5

Links

Table of n, a(n) for n=1..25.

Example

Maximal 8 X 8 example
.0.0.0.0.0.0.0.0
.0.1.0.0.0.0.1.0
.1.1.1.0.0.1.1.1
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.1.1.1.0.0.1.1.1
.0.1.0.0.0.0.1.0
.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A038255 A075501 A089504 * A113365 A293172 A145356

Adjacent sequences: A145924 A145925 A145926 * A145928 A145929 A145930

Keyword

nonn

Author

R. H. Hardin, Oct 25 2008

Status

approved