A197745 - OEIS

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A197745

Number of n X 3 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 3,3,0,1,0 for x=0,1,2,3,4.

2, 12, 66, 212, 921, 4086, 17332, 75122, 326124, 1408419, 6097753, 26404858, 114255411, 494519798, 2140532037, 9264510866, 40098753497, 173557720814, 751196491106, 3251349837567, 14072600064116, 60909443628883, 263630086389334, 1141051836433576, 4938735140721662

(list; graph; refs; listen; history; text; internal format)

OFFSET

1,1

COMMENTS

Every 0 is next to 0 3's, every 1 is next to 1 3's, every 2 is next to 2 0's, every 3 is next to 3 1's, every 4 is next to 4 0's.

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..200

FORMULA

Empirical: a(n) = 2*a(n-1) +3*a(n-2) +26*a(n-3) +20*a(n-4) +24*a(n-5) -62*a(n-6) -166*a(n-7) -99*a(n-8) +128*a(n-9) +383*a(n-10) +75*a(n-11) -563*a(n-12) -540*a(n-13) +86*a(n-14) +624*a(n-15) +663*a(n-16) +220*a(n-17) -159*a(n-18) -266*a(n-19) -229*a(n-20) -125*a(n-21) -30*a(n-22) +12*a(n-23) +4*a(n-24).

EXAMPLE

Some solutions for n=4:

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

..3..1..0....2..2..0....0..4..0....0..0..2....2..0..0....2..2..2....0..1..0

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

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

CROSSREFS

Column 3 of A197750.

Sequence in context: A372369 A369111 A334772 * A323925 A039633 A265451

Adjacent sequences: A197742 A197743 A197744 * A197746 A197747 A197748

KEYWORD

nonn

AUTHOR

R. H. Hardin, Oct 17 2011

STATUS

approved