A224644 - OEIS

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

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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