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

1,1

Comments

Column 2 of A213697

Links

Table of n, a(n) for n=1..12.

Example

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

Crossrefs

Sequence in context: A158509 A072290 A258295 * A112127 A364942 A142996

Adjacent sequences: A213688 A213689 A213690 * A213692 A213693 A213694

Keyword

nonn

Author

R. H. Hardin Jun 18 2012

Status

approved