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A260973 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00001001 or 00100101. 1
48, 91, 204, 483, 1146, 2755, 6526, 15419, 36518, 86831, 206258, 489087, 1159490, 2751195, 6530006, 15494419, 36755918, 87199191, 206899498, 490917751, 1164739402, 2763371171, 6556331950, 15555736875, 36907711926, 87566685887 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) - 2*a(n-2) + 4*a(n-3) + 3*a(n-4) + 6*a(n-5) + 4*a(n-6) + 16*a(n-8) for n>9.

Empirical g.f.: x*(48 - 5*x + 118*x^2 + 65*x^3 + 80*x^4 + 52*x^5 + 26*x^6 + 256*x^7 - 208*x^8) / (1 - 2*x + 2*x^2 - 4*x^3 - 3*x^4 - 6*x^5 - 4*x^6 - 16*x^8). - Colin Barker, Dec 29 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 1 of A260980.

Sequence in context: A204647 A260980 A260070 * A260063 A211723 A274899

Adjacent sequences:  A260970 A260971 A260972 * A260974 A260975 A260976

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 06 2015

STATUS

approved

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Last modified January 26 06:32 EST 2021. Contains 340434 sequences. (Running on oeis4.)