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A304004 Number of n X 2 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
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 A373718
KEYWORD
nonn
AUTHOR
R. H. Hardin, May 04 2018
STATUS
approved

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Last modified July 21 13:28 EDT 2024. Contains 374474 sequences. (Running on oeis4.)