login
The OEIS is supported by the many generous donors to the OEIS Foundation.

 

Logo
Hints
(Greetings from The On-Line Encyclopedia of Integer Sequences!)
A229473 Number of defective 4-colorings of an n X 2 0..3 array connected horizontally, antidiagonally and vertically with exactly one mistake, and colors introduced in row-major 0..3 order. 1

%I #10 Sep 17 2018 14:17:48

%S 1,6,42,248,1312,6528,31232,145408,663552,2981888,13238272,58195968,

%T 253755392,1098907648,4731174912,20266876928,86436216832,367219703808,

%U 1554778161152,6562710028288,27625229647872,115998476730368

%N Number of defective 4-colorings of an n X 2 0..3 array connected horizontally, antidiagonally and vertically with exactly one mistake, and colors introduced in row-major 0..3 order.

%H R. H. Hardin, <a href="/A229473/b229473.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-1) - 16*a(n-2) for n>4.

%F Conjectures from _Colin Barker_, Sep 17 2018: (Start)

%F G.f.: x*(1 - 2*x + 10*x^2 + 8*x^3) / (1 - 4*x)^2.

%F a(n) = 2^(2*n-5) * (10*n-9) for n>2.

%F (End)

%e Some solutions for n=4:

%e ..0..1....0..0....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..0

%e ..2..0....1..2....2..0....2..2....2..3....2..0....2..0....2..3....2..1....1..2

%e ..0..2....3..1....1..2....3..0....0..2....2..3....0..3....1..2....0..3....3..0

%e ..3..0....2..3....2..0....2..3....2..0....1..2....2..0....1..0....2..0....1..3

%Y Column 2 of A229479.

%K nonn

%O 1,2

%A _R. H. Hardin_, Sep 24 2013

Lookup | Welcome | Wiki | Register | Music | Plot 2 | Demos | Index | Browse | More | WebCam
Contribute new seq. or comment | Format | Style Sheet | Transforms | Superseeker | Recents
The OEIS Community | Maintained by The OEIS Foundation Inc.

License Agreements, Terms of Use, Privacy Policy. .

Last modified March 28 05:02 EDT 2024. Contains 371235 sequences. (Running on oeis4.)