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A228685 Number of 4 X n binary arrays with no two ones adjacent horizontally, diagonally or antidiagonally. 1
16, 41, 313, 1152, 6737, 28977, 152048, 699833, 3508329, 16628064, 81753697, 392401121, 1913315024, 9233466953, 44861599897, 217002245696, 1052716150641, 5097234627985, 24711403148208, 119703506867161, 580159930998217 (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) = 2*a(n-1) + 16*a(n-2) - 7*a(n-3) - 18*a(n-4).

Empirical g.f.: x*(1 + x)*(16 - 7*x - 18*x^2) / (1 - 2*x - 16*x^2 + 7*x^3 + 18*x^4). - Colin Barker, Sep 12 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

CROSSREFS

Row 4 of A228683.

Sequence in context: A227816 A200408 A280184 * A317761 A318340 A318072

Adjacent sequences:  A228682 A228683 A228684 * A228686 A228687 A228688

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 30 2013

STATUS

approved

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Last modified May 17 08:05 EDT 2022. Contains 353741 sequences. (Running on oeis4.)