A224644 Number of (n+2) X 3 0..1 matrices with each 3 X 3 subblock having the same population.

512, 1280, 3200, 8000, 22400, 62720, 175616, 514304, 1506176, 4410944, 13125248, 39055616, 116214272, 347690240, 1040220800, 3112136000, 9327881600, 27958088960, 83797669376, 251316410624, 753719509376, 2260469570624

Offset

1,1

Links

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

Formula

Empirical: a(n) = 4*a(n-1) - 3*a(n-2) + 12*a(n-3) - 48*a(n-4) + 36*a(n-5) - 27*a(n-6) + 108*a(n-7) - 81*a(n-8).

Empirical g.f.: 64*x*(8 - 12*x - 6*x^2 - 111*x^3 + 144*x^4 + 27*x^5 + 270*x^6 - 324*x^7) / ((1 - x)*(1 - 3*x)*(1 - 3*x^3)*(1 - 9*x^3)). - Colin Barker, Sep 02 2018

Example

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

Crossrefs

Column 1 of A224651.

Sequence in context: A202454 A230543 A224651 * A258726 A220583 A195092

Adjacent sequences: A224641 A224642 A224643 * A224645 A224646 A224647

Keyword

nonn

Author

R. H. Hardin, Apr 13 2013

Status

approved