A259421 Number of (n+1) X (2+1) 0..1 arrays with each 2 X 2 subblock having clockwise pattern 0000 0001 0011 or 0111.

43, 243, 1366, 7695, 43347, 244228, 1376077, 7753553, 43687910, 246163281, 1387029593, 7815349472, 44036333771, 248126951851, 1398095180302, 7877701886559, 44387669863035, 250106600625676, 1409249728938893

Offset

1,1

Links

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

Formula

Empirical: a(n) = 6*a(n-1) + 2*a(n-2) - 22*a(n-3) - 6*a(n-4) + 6*a(n-5) + a(n-6).

Empirical g.f.: x*(43 - 15*x - 178*x^2 - 41*x^3 + 49*x^4 + 8*x^5) / (1 - 6*x - 2*x^2 + 22*x^3 + 6*x^4 - 6*x^5 - x^6). - Colin Barker, Dec 25 2018

Example

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

Crossrefs

Column 2 of A259427.

Sequence in context: A362407 A158080 A142450 * A202008 A258214 A262915

Adjacent sequences: A259418 A259419 A259420 * A259422 A259423 A259424

Keyword

nonn

Author

R. H. Hardin, Jun 26 2015

Status

approved