The On-Line Encyclopedia of Integer Sequences (OEIS)

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A304128

Number of nX3 0..1 arrays with every element unequal to 0, 1, 3 or 6 king-move adjacent elements, with upper left element zero.
(history; published version)

#4 by R. H. Hardin at Mon May 07 07:55:08 EDT 2018

STATUS

editing

approved

#3 by R. H. Hardin at Mon May 07 07:55:06 EDT 2018

LINKS

R. H. Hardin, <a href="/A304128/b304128.txt">Table of n, a(n) for n = 1..210</a>

#2 by R. H. Hardin at Mon May 07 07:54:40 EDT 2018

NAME

allocated for R. H. Hardin

Number of nX3 0..1 arrays with every element unequal to 0, 1, 3 or 6 king-move adjacent elements, with upper left element zero.

DATA

3, 7, 9, 19, 33, 53, 89, 155, 261, 439, 749, 1271, 2149, 3647, 6189, 10487, 17781, 30159, 51133, 86695, 147013, 249279, 422669, 716695, 1215253, 2060591, 3493981, 5924487, 10045669, 17033631, 28882605, 48973943, 83041205, 140806415, 238754301

OFFSET

1,1

COMMENTS

Column 3 of A304133.

FORMULA

Empirical: a(n) = a(n-1) +2*a(n-3) for n>7

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Cf. A304133.

KEYWORD

allocated

nonn

AUTHOR

R. H. Hardin, May 07 2018

STATUS

approved

editing

#1 by R. H. Hardin at Mon May 07 07:53:06 EDT 2018

NAME

allocated for R. H. Hardin

KEYWORD

allocated

STATUS

approved