A146142 - OEIS

A146142

Number of n X n binary arrays symmetric under 90 degree rotation with all ones connected only in a 5-point barb 1,1 1,2 2,2 2,3 3,2 in any orientation.

1, 1, 1, 1, 1, 3, 23, 43, 81, 319, 1397, 6447, 41775, 230237, 1798489, 13587111, 143546329, 1450499749, 20575847369, 276390467445, 5233548027451, 93375391444657

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,6

LINKS

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

EXAMPLE

Maximal 8 X 8 example

.0.0.0.0.1.0.0.0

.0.0.0.0.1.1.0.0

.0.1.0.1.1.0.0.0

.1.1.1.0.0.1.0.0

.0.0.1.0.0.1.1.1

.0.0.0.1.1.0.1.0

.0.0.1.1.0.0.0.0

.0.0.0.1.0.0.0.0

CROSSREFS

Sequence in context: A319976 A117738 A014582 * A105854 A160022 A307530

Adjacent sequences: A146139 A146140 A146141 * A146143 A146144 A146145

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 27 2008

STATUS

approved