A145968 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a one by five or five by one block.

1, 1, 1, 1, 1, 1, 2, 3, 5, 7, 16, 27, 69, 151, 481, 1224, 4362, 12863, 54770, 198381, 1006602, 4307827, 25870297, 130523404, 917353447, 5499437681, 46147817424, 329292463469, 3264965678695, 27531225103405

Offset

1,7

Links

Table of n, a(n) for n=1..30.

Example

Maximal 8 X 8 example
.0.0.1.1.1.1.1.0
.0.0.0.0.0.0.0.1
.1.0.0.0.0.0.0.1
.1.0.0.0.0.0.0.1
.1.0.0.0.0.0.0.1
.1.0.0.0.0.0.0.1
.1.0.0.0.0.0.0.0
.0.1.1.1.1.1.0.0

Crossrefs

Sequence in context: A319913 A073436 A094575 * A343537 A192579 A215658

Adjacent sequences: A145965 A145966 A145967 * A145969 A145970 A145971

Keyword

nonn

Author

R. H. Hardin, Oct 25 2008

Status

approved