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A185479 Number of (n+1) X 2 binary arrays with every 2 X 2 subblock determinant equal to some horizontal or vertical neighbor 2 X 2 subblock determinant. 2
0, 30, 76, 234, 632, 1832, 5182, 14860, 42346, 121016, 345376, 986330, 2815960, 8040658, 22957720, 65550976, 187164486, 534405148, 1525866290, 4356753200, 12439678168, 35518569746, 101414891304, 289566302122, 826788250864 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 1 of A185487.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) + a(n-2) - 5*a(n-3) + 3*a(n-4) - 2*a(n-6) for n>7.

Empirical g.f.: 2*x^2*(15 - 7*x - 12*x^2 + 2*x^3 - 4*x^4 - 2*x^5) / (1 - 3*x - x^2 + 5*x^3 - 3*x^4 + 2*x^6). - Colin Barker, Feb 27 2018

EXAMPLE

Some solutions for 3 X 2:

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

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

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

CROSSREFS

Cf. A185487.

Sequence in context: A308137 A179321 A039517 * A045560 A159219 A098998

Adjacent sequences:  A185476 A185477 A185478 * A185480 A185481 A185482

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jan 28 2011

STATUS

approved

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Last modified December 14 22:42 EST 2019. Contains 329987 sequences. (Running on oeis4.)