A251286 Number of (n+1) X (2+1) 0..1 arrays with every 2 X 2 subblock having a single 1 or two 1s on the same edge or main diagonally.

22, 71, 219, 701, 2193, 6980, 21966, 69681, 219860, 696284, 2199557, 6960357, 21999804, 69591126, 220014756, 695843558, 2200194145, 6958021138, 22001843859, 69577286765, 220014836192, 695749296057, 2200100105526, 6957283657381

Offset

1,1

Links

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

Formula

Empirical: a(n) = 2*a(n-1) + 7*a(n-2) - 9*a(n-3) - 7*a(n-4) + 7*a(n-5) for n>6.

Empirical g.f.: x*(22 + 27*x - 77*x^2 - 36*x^3 + 51*x^4 + x^5) / (1 - 2*x - 7*x^2 + 9*x^3 + 7*x^4 - 7*x^5). - Colin Barker, Nov 28 2018

Example

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

Crossrefs

Column 2 of A251292.

Sequence in context: A334034 A044160 A044541 * A080861 A241521 A143838

Adjacent sequences: A251283 A251284 A251285 * A251287 A251288 A251289

Keyword

nonn

Author

R. H. Hardin, Dec 01 2014

Status

approved