The On-Line Encyclopedia of Integer Sequences (OEIS)

Revision History for A221196 (Bold, blue-underlined text is an addition; faded, red-underlined text is a ~~deletion~~.)
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A221196

Number of n X 3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2.
(history; published version)

#11 by Susanna Cuyler at Sat Aug 04 06:40:53 EDT 2018

STATUS

reviewed

approved

#10 by Michel Marcus at Sat Aug 04 06:10:17 EDT 2018

STATUS

proposed

reviewed

#9 by Colin Barker at Sat Aug 04 06:01:56 EDT 2018

STATUS

editing

proposed

#8 by Colin Barker at Sat Aug 04 06:01:22 EDT 2018

NAME

Number of nX3 n X 3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2.

COMMENTS

Column 3 of A221200.

FORMULA

Empirical: a(n) = 6*a(n-1) - 6*a(n-2) - 2*a(n-3).

Empirical g.f.: 2*x*(1 - x - x^2) / (1 - 6*x + 6*x^2 + 2*x^3). - Colin Barker, Aug 04 2018

EXAMPLE

Some solutions for n=3:

CROSSREFS

Cf. A221200.

AUTHOR

R. H. Hardin , Jan 04 2013

STATUS

approved

editing

#7 by R. H. Hardin at Fri Jan 04 12:33:19 EST 2013

STATUS

editing

approved

#6 by R. H. Hardin at Fri Jan 04 12:33:17 EST 2013

COMMENTS

Column 3 of A211200A221200

STATUS

approved

editing

#5 by R. H. Hardin at Fri Jan 04 12:24:37 EST 2013

STATUS

editing

approved

#4 by R. H. Hardin at Fri Jan 04 12:24:34 EST 2013

LINKS

R. H. Hardin, <a href="/A221196/b221196.txt">Table of n, a(n) for n = 1..33</a>

#3 by R. H. Hardin at Fri Jan 04 12:24:06 EST 2013

NAME

allocated for R. H. Hardin

Number of nX3 arrays of occupancy after each element moves to some horizontal, diagonal or antidiagonal neighbor, with no occupancy greater than 2

DATA

2, 10, 46, 212, 976, 4492, 20672, 95128, 437752, 2014400, 9269632, 42655888, 196288736, 903257824, 4156502752, 19126892096, 88015820416, 405020564416, 1863774679808, 8576493051520, 39466269101440, 181611106939904

OFFSET

1,1

COMMENTS

Column 3 of A211200

FORMULA

Empirical: a(n) = 6*a(n-1) -6*a(n-2) -2*a(n-3)

EXAMPLE

Some solutions for n=3

..0..2..0....0..2..0....1..2..0....1..2..1....1..2..1....1..2..0....0..2..1

..1..2..2....0..2..2....0..2..1....1..2..0....0..2..1....1..2..0....0..2..2

..0..2..0....0..2..1....0..2..1....0..2..0....0..2..0....0..2..1....0..2..0

KEYWORD

allocated

nonn

AUTHOR

R. H. Hardin Jan 04 2013

STATUS

approved

editing

#2 by R. H. Hardin at Fri Jan 04 12:22:42 EST 2013

KEYWORD

allocating

allocated