A145760 Number of n X n binary arrays symmetric about main diagonal with all ones connected only either three adjacent vertically or three adjacent horizontally.

1, 1, 1, 3, 8, 27, 96, 569, 4093, 37611, 421080, 6366190, 123605120, 3088656877, 98116765714, 4039581343182, 214357411746908, 14651947137883915, 1285925403332066988, 145385760960996273023, 21168918836708595100735

Offset

1,4

Links

Table of n, a(n) for n=1..21.

Crossrefs

Sequence in context: A340334 A319787 A148844 * A102318 A102206 A192856

Adjacent sequences: A145757 A145758 A145759 * A145761 A145762 A145763

Keyword

nonn

Author

R. H. Hardin, Oct 17 2008

Status

approved