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A261705 Number of (n+2)X(2+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00000101 or 00000111. 1
76, 134, 270, 462, 892, 1751, 3299, 6324, 12389, 23874, 46352, 90232, 175147, 340107, 662278, 1287201, 2502792, 4868654, 9469734, 18415483, 35823639, 69677328, 135524601, 263610130, 512755352, 997337880, 1939945931, 3773395523 (list; graph; refs; listen; history; text; internal format)
OFFSET

1,1

COMMENTS

Column 2 of A261709.

LINKS

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

FORMULA

Empirical: a(n) = 2*a(n-1) +a(n-2) -a(n-3) -6*a(n-5) +4*a(n-6) -5*a(n-7) +2*a(n-8) +11*a(n-9) -3*a(n-10) -2*a(n-12) -6*a(n-14) +4*a(n-15) for n>17

EXAMPLE

Some solutions for n=7

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

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

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

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

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

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

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

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

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

CROSSREFS

Cf. A261709.

Sequence in context: A256084 A039486 A092890 * A248532 A186896 A202173

Adjacent sequences:  A261702 A261703 A261704 * A261706 A261707 A261708

KEYWORD

nonn

AUTHOR

R. H. Hardin, Aug 28 2015

STATUS

approved

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Last modified May 28 04:54 EDT 2020. Contains 334671 sequences. (Running on oeis4.)