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A139009
Number of n X n symmetric binary matrices containing no more than one 1 in any 3 X 3 sub-block.
1
1, 2, 3, 4, 10, 29, 73, 255, 1166, 5371, 29682, 210876, 1671283, 15280803, 171861787, 2259744342, 34374508575, 625277335018, 13461221324518, 338565697760175, 10066909617112085, 354314901636357736, 14658961195961880848
OFFSET
0,2
LINKS
R. H. Hardin, May 31 2008, Table of n, a(n) for n = 0..28
CROSSREFS
Sequence in context: A332838 A123700 A005433 * A191224 A359995 A272523
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 31 2008
STATUS
approved