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A141513
Number of n X n binary matrices, symmetric under 90-degree rotation, with no more than 3 ones in any 2 X 2 subblock.
1
1, 2, 1, 7, 8, 101, 207, 5120, 20417, 961969, 7321136, 661511545, 9650955373, 1669696876968, 46646811310045, 15458287165896835, 827194455797432320, 525025121630724209885, 53809855627730048960875
OFFSET
0,2
LINKS
CROSSREFS
Sequence in context: A199964 A217107 A320432 * A258058 A238223 A102817
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 10 2008
STATUS
approved