A146867 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1101-1111 pattern in any orientation.

1, 1, 1, 1, 1, 1, 1, 5, 9, 21, 33, 55, 141, 887, 2729, 13023, 38545, 182567, 834697, 7193987, 40372625, 350655929

Offset

1,8

Links

Table of n, a(n) for n=1..22.

Example

Maximal 8 X 8 example
.0.0.1.0.1.1.0.0
.0.0.1.1.1.1.0.0
.1.1.0.0.0.0.1.1
.0.1.0.0.0.0.1.1
.1.1.0.0.0.0.1.0
.1.1.0.0.0.0.1.1
.0.0.1.1.1.1.0.0
.0.0.1.1.0.1.0.0

Crossrefs

Sequence in context: A211427 A273410 A273486 * A068481 A146827 A297360

Adjacent sequences: A146864 A146865 A146866 * A146868 A146869 A146870

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved