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A304143 Number of nX2 0..1 arrays with every element unequal to 1, 2, 3 or 6 king-move adjacent elements, with upper left element zero. 4
1, 7, 14, 33, 70, 157, 346, 769, 1710, 3813, 8514, 19049, 42678, 95757, 215114, 483793, 1089150, 2454197, 5534546, 12490169, 28205510, 63730653, 144073434, 325848609, 737262478, 1668717957, 3778162914, 8556569353, 19383222230, 43918469037 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A304149.

LINKS

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

FORMULA

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

Empirical g.f: x -x^2*(-7+16*x^2+24*x^3+12*x^4) / ( (2*x-1) *(1+x) *(2*x^3+2*x^2+x-1) ). - R. J. Mathar, May 08 2018

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A304149.

Sequence in context: A058530 A293359 A134384 * A055780 A161814 A333594

Adjacent sequences:  A304140 A304141 A304142 * A304144 A304145 A304146

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 07 2018

STATUS

approved

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Last modified September 21 02:46 EDT 2020. Contains 337266 sequences. (Running on oeis4.)