A251142 Number of (n+1) X (n+1) 0..2 arrays with every 2 X 2 subblock summing to 4 and no 2 X 2 subblock having exactly two nonzero entries.

13, 49, 143, 401, 1061, 2763, 7101, 18193, 46575, 119441, 307045, 791499, 2045725

Offset

1,1

Comments

Diagonal of A251149.

Links

Table of n, a(n) for n=1..13.

Example

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

Crossrefs

Cf. A251149.

Sequence in context: A158480 A009951 A274974 * A319086 A146287 A289999

Adjacent sequences: A251139 A251140 A251141 * A251143 A251144 A251145

Keyword

nonn

Author

R. H. Hardin, Nov 30 2014

Status

approved