A139017 Number of n X n symmetric binary matrices containing no more than seven 1s in any 3 X 3 sub-block.

1, 2, 8, 60, 906, 27189, 1613401, 189475577, 44047431458, 20270048678813, 18464881592730174, 33296006308979741676, 118848050819226253876856, 839743872159535017880129008, 11745095000736439254980601740977, 325177925025179018978272596740130128

Offset

0,2

Links

Table of n, a(n) for n=0..15.

Crossrefs

Sequence in context: A192412 A191553 A321979 * A322012 A188324 A368450

Adjacent sequences: A139014 A139015 A139016 * A139018 A139019 A139020

Keyword

nonn

Author

R. H. Hardin, May 31 2008

Status

approved