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A261704
Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00000101 or 00000111.
1
48, 76, 172, 338, 628, 1298, 2752, 5526, 10972, 22462, 46160, 93354, 188556, 384154, 782784, 1587790, 3221196, 6550678, 13318688, 27044962, 54927964, 111631314, 226840208, 460792838, 936118684, 1902095342, 3864635632, 7851378074
OFFSET
1,1
LINKS
FORMULA
Empirical: a(n) = a(n-1) + a(n-2) + a(n-3) + 5*a(n-4) - 3*a(n-5) - 5*a(n-6) + 3*a(n-7) - 4*a(n-8) + 2*a(n-9) for n>11.
Empirical g.f.: 2*x*(24 + 14*x + 24*x^2 + 21*x^3 - 99*x^4 - 38*x^5 + 48*x^6 - 45*x^7 + 47*x^8 - 6*x^9 - 2*x^10) / ((1 - x)*(1 - x^2 - 2*x^3 - 7*x^4 - 4*x^5 + x^6 - 2*x^7 + 2*x^8)). - Colin Barker, Dec 31 2018
EXAMPLE
Some solutions for n=7:
..0..0..1....0..0..0....1..0..1....0..0..0....1..0..0....0..0..0....1..0..0
..0..0..0....0..1..0....0..0..0....0..1..0....1..1..0....1..0..0....0..0..0
..0..0..1....1..0..0....0..0..0....0..0..1....1..0..0....0..0..0....1..0..0
..0..0..0....0..0..0....1..0..0....0..0..0....0..0..0....0..0..0....0..0..0
..0..0..0....0..0..0....0..1..0....0..0..0....0..0..0....0..0..1....0..0..0
..0..1..0....0..0..1....0..0..0....0..0..1....0..0..1....0..0..0....0..0..1
..0..0..1....0..0..0....0..0..0....0..0..0....0..0..0....0..0..0....0..1..1
..0..0..0....0..0..1....1..0..0....0..0..0....0..0..0....0..1..0....0..0..1
..0..0..0....0..1..0....0..1..0....0..1..0....0..0..1....0..1..0....0..0..0
CROSSREFS
Column 1 of A261709.
Sequence in context: A328370 A143722 A261709 * A260370 A260363 A261553
KEYWORD
nonn
AUTHOR
R. H. Hardin, Aug 28 2015
STATUS
approved