A186842 Number of (n+1) X 2 binary arrays with no 2 X 2 subblock diagonal sum less antidiagonal sum equal to any horizontal or vertical neighbor 2 X 2 subblock diagonal sum less antidiagonal sum.

16, 50, 162, 512, 1626, 5182, 16476, 52378, 166634, 529984, 1685474, 5360790, 17050124, 54227106, 172469170, 548538048, 1744617610, 5548740302, 17647726972, 56128428362, 178515953178, 567768430400, 1805782389330, 5743274639206

Offset

1,1

Comments

Column 1 of A186850.

Links

R. H. Hardin, Table of n, a(n) for n = 1..200

Formula

Empirical: a(n) = a(n-1) + 3*a(n-2) + 10*a(n-3) + 8*a(n-4).

Empirical g.f.: 2*x*(8 + 17*x + 32*x^2 + 20*x^3) / (1 - x - 3*x^2 - 10*x^3 - 8*x^4). - Colin Barker, Apr 19 2018

Example

Some solutions for 3 X 2:
..0..1....0..1....1..0....1..1....0..1....0..1....1..1....1..0....1..0....0..1
..0..1....0..1....1..0....1..0....1..0....0..0....0..1....1..0....1..1....1..0
..0..0....1..0....1..1....1..1....0..0....0..0....0..1....0..1....1..0....1..1

Crossrefs

Cf. A186850.

Sequence in context: A235573 A186850 A235566 * A231840 A199809 A121863

Adjacent sequences: A186839 A186840 A186841 * A186843 A186844 A186845

Keyword

nonn

Author

R. H. Hardin, Feb 27 2011

Status

approved