A268974 Number of 4Xn 0..2 arrays with some element plus some horizontally or antidiagonally adjacent neighbor totalling two not more than once.

81, 1728, 15552, 136080, 1125360, 9093528, 72081792, 563173128, 4349328912, 33272350344, 252534743280, 1904015932416, 14274182767248, 106487231224248, 791006745522096, 5853579437553624, 43172409083833728, 317460508504648992

Offset

1,1

Comments

Row 4 of A268971.

Links

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

Formula

Empirical: a(n) = 18*a(n-1) -111*a(n-2) +282*a(n-3) -333*a(n-4) +180*a(n-5) -36*a(n-6) for n>12

Example

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

Crossrefs

Cf. A268971.

Sequence in context: A050634 A065791 A237503 * A206677 A237091 A253306

Adjacent sequences: A268971 A268972 A268973 * A268975 A268976 A268977

Keyword

nonn

Author

R. H. Hardin, Feb 16 2016

Status

approved