A146637 Number of n X n binary arrays symmetric about main diagonal with all ones connected only in a 1010-1111-0100 pattern in any orientation.

1, 1, 1, 1, 1, 7, 21, 49, 223, 1043, 7899, 74561, 730567, 8688119, 134449641, 2597702163, 64827359403, 1993658503781, 73350618685271, 3327101809889351

Offset

1,6

Links

Table of n, a(n) for n=1..20.

Example

Maximal 8 X 8 example
.0.0.0.1.1.0.0.0
.0.0.0.0.1.1.0.0
.0.0.0.1.1.0.1.0
.1.0.1.0.1.0.1.1
.1.1.1.1.0.1.1.0
.0.1.0.0.1.0.1.1
.0.0.1.1.1.1.0.0
.0.0.0.1.0.1.0.0

Crossrefs

Sequence in context: A011927 A163723 A146669 * A146701 A146613 A083012

Adjacent sequences: A146634 A146635 A146636 * A146638 A146639 A146640

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved