A206089 Number of (n+1) X 4 0..2 arrays with every 2 X 3 or 3 X 2 subblock having exactly two counterclockwise and two clockwise edge increases.

972, 2016, 4560, 13344, 33792, 86496, 240192, 608256, 1556928, 4323456, 10948608, 28024704, 77822208, 197074944, 504444672, 1400799744, 3547348992, 9080004096, 25214395392, 63852281856, 163440073728, 453859117056, 1149341073408

Offset

1,1

Comments

Column 3 of A206094.

Links

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

Formula

Empirical: a(n) = 18*a(n-3) for n>6.

Example

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

Crossrefs

Sequence in context: A217161 A243861 A171771 * A217162 A203375 A183359

Adjacent sequences: A206086 A206087 A206088 * A206090 A206091 A206092

Keyword

nonn

Author

R. H. Hardin, Feb 03 2012

Status

approved