

A318031


Number of nX2 0..1 arrays with every element unequal to 0, 1, 3 or 4 horizontally, vertically or antidiagonally adjacent elements, with upper left element zero.


2



2, 3, 6, 11, 22, 46, 91, 182, 371, 746, 1498, 3027, 6102, 12283, 24766, 49926, 100587, 202726, 408611, 823442, 1659506, 3344611, 6740518, 13584427, 27377702, 55175838, 111198651, 224105366, 451652627, 910240506, 1834460106, 3697093427
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OFFSET

1,1


COMMENTS

Column 2 of A318037.


LINKS

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


FORMULA

Empirical: a(n) = a(n1) +4*a(n3) +a(n5) a(n6)


EXAMPLE

Some solutions for n=5
..0..0. .0..0. .0..0. .0..1. .0..0. .0..1. .0..0. .0..0. .0..0. .0..0
..0..1. .0..0. .0..1. .0..0. .1..0. .0..0. .1..0. .1..0. .0..0. .1..0
..0..0. .0..0. .0..0. .0..0. .1..1. .0..0. .0..0. .0..0. .0..0. .0..0
..0..0. .1..0. .0..0. .1..0. .1..1. .1..0. .0..1. .0..0. .0..0. .0..0
..1..0. .0..0. .0..0. .1..1. .0..1. .0..0. .0..0. .0..0. .1..0. .1..0


CROSSREFS

Cf. A318037.
Sequence in context: A244521 A096202 A036653 * A316500 A123769 A093304
Adjacent sequences: A318028 A318029 A318030 * A318032 A318033 A318034


KEYWORD

nonn


AUTHOR

R. H. Hardin, Aug 13 2018


STATUS

approved



