A261705 Number of (n+2)X(2+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00000101 or 00000111.

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

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