A146276 Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 110-111-111 pattern in any orientation.

1, 1, 1, 1, 3, 5, 11, 23, 41, 95, 251, 683, 2475, 8891, 33925, 147349, 637035, 3134145, 16878377, 99607453, 667424329, 4848478029, 38002637893, 331471680853, 3049547921723, 31341827546071

Offset

1,5

Links

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

Example

Maximal 8 X 8 example
.0.1.1.0.0.1.1.0
.1.1.1.0.0.1.1.1
.1.1.1.0.0.1.1.1
.0.0.0.0.0.0.0.0
.0.0.0.0.0.0.0.0
.1.1.1.0.0.1.1.1
.1.1.1.0.0.1.1.1
.0.1.1.0.0.1.1.0

Crossrefs

Sequence in context: A280773 A109927 A347287 * A155753 A133914 A169913

Adjacent sequences: A146273 A146274 A146275 * A146277 A146278 A146279

Keyword

nonn

Author

R. H. Hardin

Status

approved