A284159 Number of n X 2 0..1 arrays with the number of 1's horizontally or vertically adjacent to some 0 equal to the number of 0's adjacent to some 1, with top left element zero.

2, 4, 13, 42, 134, 467, 1689, 6210, 23178, 87336, 331172, 1262635, 4836199, 18592719, 71697865, 277195002, 1074041216, 4169581090, 16214541562, 63150645344, 246288102302, 961707595682, 3759467766802, 14711266580343, 57620439699189

Offset

1,1

Comments

Column 2 of A284165.

Links

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

Example

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

Crossrefs

Cf. A284165.

Sequence in context: A259239 A243107 A002771 * A050624 A135501 A001548

Adjacent sequences: A284156 A284157 A284158 * A284160 A284161 A284162

Keyword

nonn

Author

R. H. Hardin, Mar 21 2017

Status

approved