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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A228750 Number of n X 4 binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally. 1

%I #10 Sep 12 2018 15:08:35

%S 3,20,126,780,4808,29608,182288,1122240,6908896,42533440,261849728,

%T 1612032128,9924194048,61096565760,376130326016,2315580595200,

%U 14255467112448,87761291061248,540287045521408,3326182739886080

%N Number of n X 4 binary arrays with top left element equal to 1 and no two ones adjacent horizontally or antidiagonally.

%H R. H. Hardin, <a href="/A228750/b228750.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 8*a(n-1) - 12*a(n-2) + 4*a(n-3).

%F Empirical g.f.: x*(3 - 4*x + 2*x^2) / (1 - 8*x + 12*x^2 - 4*x^3). - _Colin Barker_, Sep 12 2018

%e Some solutions for n=4:

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

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

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

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

%Y Column 4 of A228754.

%K nonn

%O 1,1

%A _R. H. Hardin_, Sep 02 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.

Last modified September 16 07:48 EDT 2024. Contains 375959 sequences. (Running on oeis4.)