A261549 Number of (n+2)X(2+2) 0..1 arrays with each 3X3 subblock having clockwise perimeter pattern 00000001 00000101 or 00001011.

80, 132, 269, 484, 871, 1702, 3230, 6084, 11656, 22140, 41998, 80163, 152575, 290154, 552862, 1052566, 2003661, 3815643, 7265371, 13832801, 26339615, 50153430, 95494793, 181830620, 346224829, 659237773, 1255247777, 2390111154, 4550973946

Offset

1,1

Comments

Column 2 of A261553.

Links

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

Formula

Empirical: a(n) = 2*a(n-2) +3*a(n-3) +a(n-4) -a(n-5) +a(n-6) -2*a(n-7) -2*a(n-8) -3*a(n-9) +2*a(n-10) -a(n-11) -7*a(n-12) +3*a(n-13) -4*a(n-14) -2*a(n-15) +2*a(n-16) for n>17

Example

Some solutions for n=4
..0..0..0..1....1..0..0..1....0..1..0..1....1..1..0..1....0..0..0..0
..0..0..0..0....0..0..0..0....0..0..0..1....0..0..0..0....0..0..0..1
..1..0..0..1....1..0..0..1....0..0..0..0....1..0..0..0....1..0..0..0
..0..0..0..0....0..0..0..0....1..0..0..0....0..0..0..1....0..0..0..0
..0..0..0..0....1..0..0..1....0..0..0..1....0..0..0..0....1..0..0..1
..1..0..0..1....0..0..0..0....1..0..0..0....1..0..1..1....1..0..1..0

Crossrefs

Cf. A261553.

Sequence in context: A044003 A062376 A223087 * A068140 A365867 A349307

Adjacent sequences: A261546 A261547 A261548 * A261550 A261551 A261552

Keyword

nonn

Author

R. H. Hardin, Aug 24 2015

Status

approved