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A260602 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000101 00010001 or 00010101. 1
40, 58, 125, 241, 525, 1029, 2246, 4407, 9592, 18930, 41027, 81192, 175502, 348438, 750714, 1494859, 3211981, 6412772, 13742956, 27507848, 58807987, 117983491, 251666242, 506004675, 1077074116, 2169965427, 4609962160, 9305093538 (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) = a(n-1) + 2*a(n-2) - a(n-3) + 7*a(n-4) - 10*a(n-5) + 6*a(n-6) - 5*a(n-7) - 3*a(n-8) + 6*a(n-9) + 2*a(n-10) - 8*a(n-11) + 4*a(n-12) for n>13.

Empirical g.f.: x*(40 + 18*x - 13*x^2 + 40*x^3 - 188*x^4 + 141*x^5 - 127*x^6 + 43*x^7 + 117*x^8 - 70*x^9 - 110*x^10 + 136*x^11 - 36*x^12) / ((1 - x)*(1 - 2*x^2 - x^3 - 8*x^4 + 2*x^5 - 4*x^6 + x^7 + 4*x^8 - 2*x^9 - 4*x^10 + 4*x^11)). - Colin Barker, Dec 29 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 1 of A260609.

Sequence in context: A109730 A100333 A260609 * A116309 A126816 A259061

Adjacent sequences:  A260599 A260600 A260601 * A260603 A260604 A260605

KEYWORD

nonn

AUTHOR

R. H. Hardin, Jul 29 2015

STATUS

approved

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Last modified September 18 22:24 EDT 2020. Contains 337174 sequences. (Running on oeis4.)