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A304004 Number of nX2 0..1 arrays with every element unequal to 0, 2, 3 or 5 king-move adjacent elements, with upper left element zero. 9
1, 4, 7, 13, 26, 49, 99, 194, 387, 773, 1538, 3081, 6147, 12298, 24587, 49157, 98330, 196609, 393251, 786450, 1572883, 3145797, 6291442, 12583033, 25165827, 50331738, 100663451, 201326533, 402653578, 805306225, 1610613155, 3221225698 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 2 of A304010.

LINKS

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

FORMULA

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

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A304010.

Sequence in context: A074864 A074865 A072683 * A293342 A298346 A122552

Adjacent sequences:  A304001 A304002 A304003 * A304005 A304006 A304007

KEYWORD

nonn

AUTHOR

R. H. Hardin, May 04 2018

STATUS

approved

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Last modified October 18 08:08 EDT 2019. Contains 328146 sequences. (Running on oeis4.)