A145792 Number of n X n binary arrays symmetric about main diagonal with all ones connected only either four adjacent vertically or four adjacent horizontally.

1, 1, 1, 1, 3, 8, 27, 89, 350, 1943, 13578, 114816, 1134812, 13374912, 197153652, 3619365346, 81478825413, 2227027591689, 73860566227987, 3001388762491543, 149854380038852307, 9172310473214513455, 686434022927867658469

Offset

1,5

Links

Table of n, a(n) for n=1..23.

Crossrefs

Sequence in context: A121650 A151462 A145967 * A148834 A148835 A148836

Adjacent sequences: A145789 A145790 A145791 * A145793 A145794 A145795

Keyword

nonn

Author

R. H. Hardin, Oct 19 2008

Status

approved