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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
OFFSET
1,2
COMMENTS
Column 3 of A186168
LINKS
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: A233152 A138411 A361188 * A102279 A132464 A145155
KEYWORD
nonn
AUTHOR
R. H. Hardin Feb 13 2011
STATUS
approved