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A207270 Number of 3Xn 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 1 1 and 1 0 1 vertically 2
6, 36, 82, 217, 499, 1014, 2141, 4188, 8150, 15670, 29517, 55523, 103348, 191593, 353916, 651316, 1196664, 2193747, 4017137, 7347906, 13429145, 24530862, 44784850, 81739060, 149141623, 272067741, 496250336, 905026713, 1650411906 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A207269

LINKS

R. H. Hardin, Table of n, a(n) for n = 1..210

FORMULA

Empirical: a(n) = a(n-1) +4*a(n-2) +2*a(n-3) -12*a(n-4) -9*a(n-5) +6*a(n-6) +20*a(n-7) +6*a(n-8) -2*a(n-9) -16*a(n-10) -12*a(n-11) -4*a(n-12) +14*a(n-13) +9*a(n-14) +a(n-15) -6*a(n-16) -2*a(n-17) +a(n-19)

EXAMPLE

Some solutions for n=4

..1..0..1..0....1..1..1..0....0..0..1..0....1..0..1..0....0..0..1..0

..0..0..1..0....0..0..1..0....1..0..1..0....0..0..1..0....0..1..0..0

..0..1..0..1....0..0..1..0....0..1..0..1....0..0..1..0....1..0..0..1

CROSSREFS

Sequence in context: A208689 A207483 A207264 * A207763 A207347 A207769

Adjacent sequences:  A207267 A207268 A207269 * A207271 A207272 A207273

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 16 2012

STATUS

approved

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Last modified October 17 21:17 EDT 2021. Contains 348065 sequences. (Running on oeis4.)