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A186162 1/4 the number of nX3 0..3 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors 1
1, 48, 702, 14364, 253341, 4762206, 87054174, 1610684397, 29645381115, 546876640548, 10078456022415, 185816448936792, 3425262221153151, 63144918326035629, 1164039832228952691, 21458721711659114403 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,2

COMMENTS

Column 3 of A186168

LINKS

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

FORMULA

Empirical: a(n)=12*a(n-1)+138*a(n-2)-297*a(n-3)-1095*a(n-4)-588*a(n-5)+4871*a(n-6)+10632*a(n-7)-24375*a(n-8)+40893*a(n-9)-59724*a(n-10)-68247*a(n-11)-358891*a(n-12)+1270395*a(n-13)+391440*a(n-14)-2188134*a(n-15)+133083*a(n-16)+1270323*a(n-17)+3453273*a(n-18)+1073817*a(n-19)-5417199*a(n-20)-4448358*a(n-21)-13463172*a(n-22)-12754584*a(n-23)

EXAMPLE

Some solutions for 4X3 with a(1,1)=0

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

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

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

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

CROSSREFS

Sequence in context: A136038 A233152 A138411 * A102279 A132464 A145155

Adjacent sequences:  A186159 A186160 A186161 * A186163 A186164 A186165

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 13 2011

STATUS

approved

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Last modified June 23 05:41 EDT 2021. Contains 345395 sequences. (Running on oeis4.)