A145956 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a zee 1,1 1,2 2,2 2,3 in any orientation.

1, 1, 1, 1, 1, 3, 7, 13, 37, 103, 343, 1549, 7241, 37919, 236383, 1636125, 13465687, 128312593, 1395150187, 17424865195, 251739719221, 4153202993611, 79756129711801, 1753738354816013, 44633769685103851, 1301658659951823679

Offset

1,6

Links

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

Example

Maximal 8 X 8 example
.0.0.0.0.0.0.0.0
.0.0.0.0.1.1.0.0
.0.0.0.1.1.0.1.0
.0.0.1.0.0.1.1.0
.0.1.1.0.0.1.0.0
.0.1.0.1.1.0.0.0
.0.0.1.1.0.0.0.0
.0.0.0.0.0.0.0.0

Crossrefs

Sequence in context: A177945 A147448 A146449 * A155225 A051842 A147447

Adjacent sequences: A145953 A145954 A145955 * A145957 A145958 A145959

Keyword

nonn

Author

R. H. Hardin, Oct 25 2008

Status

approved