A213691 Half the number of (n+1)X(n+1) symmetric 0..2 arrays with no 2X2 subblock summing to 4.

11, 192, 7827, 750261, 168382284, 88681187619, 109492322533385, 317058871268862262, 2152886481426876004067, 34281579489759899253123057, 1280103594445094955653155909620, 112093309434087933528612875492895053

Offset: 1

Author

R. H. Hardin Jun 18 2012

Keywords

• nonn

Comments

Column 2 of A213697

Examples

			Some solutions for n=4
..0..0..2..0..0....0..0..2..1..0....2..2..2..1..1....0..2..0..0..1
..0..0..1..2..0....0..1..2..0..2....2..0..2..2..1....2..1..2..0..1
..2..1..1..2..2....2..2..0..0..0....2..2..1..0..2....0..2..2..2..2
..0..2..2..0..1....1..0..0..2..0....1..2..0..2..1....0..0..2..0..1
..0..0..2..1..1....0..2..0..0..0....1..1..2..1..2....1..1..2..1..1