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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 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

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

Adjacent sequences:  A250948 A250949 A250950 * A250952 A250953 A250954

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 28 2014

STATUS

approved

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Last modified December 9 03:23 EST 2021. Contains 349625 sequences. (Running on oeis4.)