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A231241
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, no adjacent elements equal, and upper left element zero.
1
0, 14, 78, 552, 3820, 26658, 185074, 1287036, 8947088, 62202118, 432432502, 3006318960, 20900215412, 145300370954, 1010142438650, 7022609687108, 48821873295640, 339414466598958, 2359642763446654, 16404468638111480
OFFSET
1,2
COMMENTS
Column 3 of A231246.
LINKS
FORMULA
Empirical: a(n) = 4*a(n-1) +16*a(n-2) +26*a(n-3) +37*a(n-4) +6*a(n-5).
Empirical g.f.: 2*x^2*(7 + 11*x + 8*x^2) / (1 - 4*x - 16*x^2 - 26*x^3 - 37*x^4 - 6*x^5). - Colin Barker, Feb 09 2018
EXAMPLE
Some solutions for n=4:
..0..1..0....0..3..2....0..3..0....0..1..0....0..3..2....0..1..2....0..1..0
..2..3..2....2..1..0....2..1..0....0..3..2....0..1..0....2..3..0....0..3..2
..0..3..0....2..3..2....2..3..2....0..3..2....0..3..0....0..3..2....2..1..0
..2..1..2....2..1..0....2..1..2....2..1..2....0..1..2....0..1..2....2..3..0
CROSSREFS
Sequence in context: A166842 A364770 A370960 * A138401 A099360 A329820
KEYWORD
nonn
AUTHOR
R. H. Hardin, Nov 06 2013
STATUS
approved