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A231044 Number of n X 3 0..3 arrays x(i,j) with each element horizontally, diagonally or antidiagonally next to at least one element with value (x(i,j)+1) mod 4 and at least one element with value (x(i,j)-1) mod 4, no adjacent elements equal, and upper left element zero. 1
0, 14, 50, 410, 2430, 16198, 103042, 667690, 4294910, 27706854, 178536322, 1150960010, 7418522110, 47819461126, 308233683970, 1986827617770, 12806735485950, 82550064227622, 532103488349058, 3429848277235530 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A231049.

LINKS

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

FORMULA

Empirical: a(n) = 3*a(n-1) +19*a(n-2) +19*a(n-3) +12*a(n-4) -8*a(n-5) +8*a(n-6).

Empirical g.f.: 2*x^2*(1 - x)*(7 + 11*x + 8*x^2) / (1 - 3*x - 19*x^2 - 19*x^3 - 12*x^4 + 8*x^5 - 8*x^6). - Colin Barker, Feb 09 2018

EXAMPLE

Some solutions for n=4:

..0..3..0....0..1..0....0..1..0....0..1..2....0..1..2....0..1..2....0..1..2

..2..1..0....2..3..2....0..3..2....0..3..2....0..3..0....2..3..2....0..3..2

..2..1..2....2..1..0....2..3..0....2..3..0....0..3..0....1..0..1....0..3..2

..0..3..0....2..3..2....2..1..2....0..1..2....0..1..2....3..2..3....2..1..2

CROSSREFS

Sequence in context: A205354 A281699 A082668 * A231076 A158519 A043132

Adjacent sequences:  A231041 A231042 A231043 * A231045 A231046 A231047

KEYWORD

nonn

AUTHOR

R. H. Hardin, Nov 03 2013

STATUS

approved

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Last modified October 21 11:05 EDT 2019. Contains 328294 sequences. (Running on oeis4.)