A195957 - OEIS

A195957

Number of nX3 0..4 arrays with each element equal to the number its horizontal and vertical neighbors unequal to itself

2, 6, 10, 16, 21, 44, 82, 144, 273, 531, 1032, 1960, 3805, 7446, 14505, 28254, 55311, 108511, 212645, 417039, 819145, 1609692, 3163058, 6217976, 12229218, 24055201, 47320658, 93104592, 183213156, 360551489, 709578685, 1396577604, 2748853048

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OFFSET

1,1

COMMENTS

Column 3 of A195962

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-2) +5*a(n-3) +5*a(n-4) -4*a(n-5) -15*a(n-6) -14*a(n-7) -a(n-8) +10*a(n-9) +2*a(n-10) -16*a(n-11) -15*a(n-12) +9*a(n-13) +29*a(n-14) +20*a(n-15) -2*a(n-16) -10*a(n-17) -4*a(n-18)

EXAMPLE

Some solutions for n=5

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

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

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

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

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

CROSSREFS

Sequence in context: A124198 A032426 A220453 * A354425 A294013 A183575

Adjacent sequences: A195954 A195955 A195956 * A195958 A195959 A195960

KEYWORD

nonn

AUTHOR

R. H. Hardin Sep 25 2011

STATUS

approved