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A250951
Number of (n+1) X (3+1) 0..1 arrays with no 2 X 2 subblock having its maximum diagonal element less than its minimum antidiagonal element.
1
209, 2744, 36016, 472712, 6204344, 81431944, 1068793208, 14027896712, 184115958136, 2416519505288, 31716786410360, 416282400363400, 5463700975560056, 71711002733396360, 941205958384596856
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = 15*a(n-1) - 24*a(n-2) - 8*a(n-3).
Empirical g.f.: x*(209 - 391*x - 128*x^2) / (1 - 15*x + 24*x^2 + 8*x^3). - Colin Barker, Nov 24 2018
EXAMPLE
Some solutions for n=3:
1 0 0 1 1 1 0 1 0 1 0 0 1 0 1 1 0 0 1 0
0 0 0 0 1 0 1 1 0 1 0 0 0 0 0 1 1 0 1 1
1 0 0 1 0 1 1 0 1 1 0 1 1 0 0 0 0 0 0 1
0 0 0 1 0 0 1 1 0 1 0 1 1 0 0 0 0 0 1 1
CROSSREFS
Column 3 of A250956.
Sequence in context: A235731 A235512 A203040 * A304765 A316509 A317463
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 28 2014
STATUS
approved