A145954 Number of n X n binary arrays symmetric under horizontal and vertical reflection with all ones connected only in a zee 1,1 1,2 2,2 2,3 in any orientation.

1, 1, 1, 1, 1, 1, 9, 9, 33, 33, 333, 333, 7127, 7127, 205501, 205501, 11166945, 11166945, 1122739259, 1122739259, 190153543115, 190153543115, 56969419979245, 56969419979245, 30406497496961445, 30406497496961445

Offset

1,7

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.0.0.0.0
.1.1.0.0.0.0.1.1
.0.1.1.0.0.1.1.0
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.0.1.1.0.0.1.1.0
.1.1.0.0.0.0.1.1
.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A146138 A147446 A146447 * A003874 A339735 A341835

Adjacent sequences: A145951 A145952 A145953 * A145955 A145956 A145957

Keyword

nonn

Author

R. H. Hardin, Oct 25 2008

Status

approved