A146870 Number of n X n binary arrays symmetric under 180 degree rotation with all ones connected only in a 1101-1111 pattern in any orientation.

1, 1, 1, 1, 17, 29, 97, 473, 2981, 21253, 221233, 1979801, 27911349, 414463777, 10310356843, 228677282931, 8215295336657, 272807472524325

Offset

1,5

Links

Table of n, a(n) for n=1..18.

Example

Maximal 8 X 8 example
.1.1.0.0.0.0.0.0
.1.0.0.0.1.1.1.1
.1.1.0.0.1.0.1.1
.1.1.0.0.0.0.0.0
.0.0.0.0.0.0.1.1
.1.1.0.1.0.0.1.1
.1.1.1.1.0.0.0.1
.0.0.0.0.0.0.1.1

Crossrefs

Sequence in context: A069755 A076727 A347530 * A146744 A103304 A104067

Adjacent sequences: A146867 A146868 A146869 * A146871 A146872 A146873

Keyword

nonn

Author

R. H. Hardin, Nov 04 2008

Status

approved