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A186120 Number of (n+1) X 2 binary arrays with every 2 X 2 subblock diagonal sum less antidiagonal sum equal to some horizontal or vertical neighbor 2 X 2 subblock diagonal sum less antidiagonal sum. 1
0, 14, 18, 50, 74, 182, 298, 678, 1186, 2566, 4690, 9830, 18498, 38006, 72914, 147974, 287554, 579222, 1135282, 2276710, 4488226, 8978102, 17768850, 35496326, 70442882, 140631254, 279616498, 558094758, 1111168738, 2217823222, 4420075090 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 1 of A186128.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 6*a(n-4) - 4*a(n-5) for n>6.

Empirical g.f.: 2*x^2*(7 - 12*x - 2*x^2 + 4*x^3 - 8*x^4) / ((1 - 2*x)*(1 - x - 2*x^2 + 2*x^3 - 2*x^4)). - Colin Barker, Apr 17 2018

EXAMPLE

Some solutions for 3 X 2:

..0..1....1..1....1..0....0..0....1..1....0..0....1..0....1..0....0..1....0..1

..0..0....0..0....1..1....1..1....0..0....0..0....0..0....1..0....0..1....1..1

..1..0....1..1....0..1....0..0....0..0....1..1....0..1....1..0....0..1....1..0

CROSSREFS

Cf. A186128.

Sequence in context: A244034 A154864 A328239 * A065343 A222576 A165228

Adjacent sequences:  A186117 A186118 A186119 * A186121 A186122 A186123

KEYWORD

nonn

AUTHOR

R. H. Hardin, Feb 13 2011

STATUS

approved

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Last modified January 23 11:42 EST 2022. Contains 350512 sequences. (Running on oeis4.)