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A261285 Number of (n+2) X (1+2) 0..1 arrays with each 3 X 3 subblock having clockwise perimeter pattern 00000001 00010101 or 01010101. 1
36, 50, 96, 166, 307, 540, 1015, 1786, 3304, 5862, 10877, 19316, 35609, 63526, 116992, 209094, 383787, 687684, 1260543, 2262114, 4138240, 7439142, 13591813, 24462924, 44638225, 80433102, 146628424, 264446262, 481653251, 869371260, 1582318631 (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-2) + 2*a(n-3) + 4*a(n-4) + 3*a(n-6) - 8*a(n-7) + 9*a(n-8) - 6*a(n-9) - 4*a(n-10) - 4*a(n-11) - 4*a(n-12) for n>13.

Empirical g.f.: x*(36 + 50*x + 60*x^2 + 44*x^3 - 33*x^4 - 18*x^5 - 116*x^6 + 106*x^7 - 231*x^8 - 78*x^9 - 72*x^10 - 36*x^11 + 28*x^12) / (1 - x^2 - 2*x^3 - 4*x^4 - 3*x^6 + 8*x^7 - 9*x^8 + 6*x^9 + 4*x^10 + 4*x^11 + 4*x^12). - Colin Barker, Dec 30 2018

EXAMPLE

Some solutions for n=4:

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

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

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

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

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

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

CROSSREFS

Column 1 of A261292.

Sequence in context: A332287 A050691 A211720 * A261257 A188243 A335104

Adjacent sequences: A261282 A261283 A261284 * A261286 A261287 A261288

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 14 2015

STATUS

approved

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Last modified November 27 06:50 EST 2022. Contains 358362 sequences. (Running on oeis4.)