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A207443 Number of 3Xn 0..1 arrays avoiding 0 0 1 and 0 1 0 horizontally and 0 0 1 and 1 0 0 vertically 1
6, 36, 108, 323, 1058, 3223, 9515, 28426, 84486, 249106, 734637, 2166526, 6380211, 18782449, 55296998, 162765970, 479038288, 1409873905, 4149367138, 12211531035, 35938252497, 105765419940, 311263342522, 916033572652, 2695845174863 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Row 3 of A207442

LINKS

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

FORMULA

Empirical: a(n) = 4*a(n-1) -5*a(n-2) +16*a(n-3) -35*a(n-4) +19*a(n-5) -48*a(n-6) +80*a(n-7) +12*a(n-8) +52*a(n-9) -92*a(n-10) -54*a(n-11) -52*a(n-12) +76*a(n-13) +43*a(n-14) +32*a(n-15) -27*a(n-16) -16*a(n-17) -11*a(n-18) +5*a(n-19) +2*a(n-21)

EXAMPLE

Some solutions for n=4

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

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

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

CROSSREFS

Sequence in context: A060521 A036141 A270205 * A207437 A199243 A172137

Adjacent sequences:  A207440 A207441 A207442 * A207444 A207445 A207446

KEYWORD

nonn

AUTHOR

R. H. Hardin Feb 17 2012

STATUS

approved

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Last modified July 31 06:15 EDT 2021. Contains 346369 sequences. (Running on oeis4.)