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A219143 Unchanging value maps: number of 2 X n binary arrays indicating the locations of corresponding elements unequal to no horizontal, diagonal or antidiagonal neighbor in a random 0..2 2 X n array. 2
1, 6, 18, 39, 96, 225, 543, 1293, 3096, 7392, 17673, 42228, 100929, 241197, 576441, 1377606, 3292314, 7868187, 18803964, 44939013, 107398431, 256668285, 613403916, 1465955712, 3503443917, 8372776200, 20009848437, 47820940581, 114285841233 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Row 2 of A219142.

LINKS

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

FORMULA

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

Empirical g.f.: x*(1 + 4*x + 5*x^2 - 2*x^3 + 4*x^4) / (1 - 2*x - x^2 + x^3 - 2*x^4). - Colin Barker, Mar 11 2018

EXAMPLE

Some solutions for n=3:

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

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

CROSSREFS

Cf. A219142.

Sequence in context: A271252 A271541 A035489 * A122061 A333713 A299256

Adjacent sequences:  A219140 A219141 A219142 * A219144 A219145 A219146

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 12 2012

STATUS

approved

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Last modified August 1 11:49 EDT 2021. Contains 346385 sequences. (Running on oeis4.)