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A232923 Number of 4Xn 0..2 arrays with no element x(i,j) adjacent to value 2-x(i,j) horizontally, diagonally or antidiagonally 1
81, 162, 1122, 5808, 33702, 186720, 1054446, 5907444, 33206862, 186398988, 1046931522, 5878727460, 33013750890, 185390166264, 1041086668026, 5846332684128, 32830815650766, 184365298149288, 1035325615443174 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 4 of A232920

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) +16*a(n-2) -3*a(n-3) -25*a(n-4) +2*a(n-5) +4*a(n-6) for n>7

EXAMPLE

Some solutions for n=5

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

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

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

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

CROSSREFS

Sequence in context: A031494 A043324 A267696 * A250655 A184003 A183995

Adjacent sequences:  A232920 A232921 A232922 * A232924 A232925 A232926

KEYWORD

nonn

AUTHOR

R. H. Hardin, Dec 02 2013

STATUS

approved

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Last modified December 11 21:15 EST 2017. Contains 295919 sequences.