A209377 1/4 the number of (n+1) X 4 0..2 arrays with every 2 X 2 subblock having distinct edge sums.

16, 34, 64, 156, 320, 840, 1792, 4848, 10496, 28704, 62464, 171456, 373760, 1027200, 2240512, 6160128, 13438976, 36954624, 80625664, 221715456, 483737600, 1330268160, 2902392832, 7981559808, 17414291456, 47889260544, 104485617664

Offset

1,1

Comments

Column 3 of A209382.

Links

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

Formula

Empirical: a(n) = 8*a(n-2) - 12*a(n-4).

Empirical g.f.: 2*x*(8 + 17*x - 32*x^2 - 58*x^3) / ((1 - 2*x^2)*(1 - 6*x^2)). - Colin Barker, Jul 09 2018

Example

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

Crossrefs

Cf. A209382.

Sequence in context: A091216 A350522 A132760 * A203446 A153819 A185459

Adjacent sequences: A209374 A209375 A209376 * A209378 A209379 A209380

Keyword

nonn

Author

R. H. Hardin, Mar 07 2012

Status

approved