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!)
A208003 Number of n X 4 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 1 1 and 1 1 0 vertically. 1

%I

%S 9,81,221,536,1711,4993,16742,53411,182247,608142,2095301,7157363,

%T 24822376,85845073,299033933,1040987192,3636447903,12703622001,

%U 44454269798,155590727603,545028524023,1909557999406,6693157243061

%N Number of n X 4 0..1 arrays avoiding 0 0 1 and 1 0 0 horizontally and 0 1 1 and 1 1 0 vertically.

%C Column 4 of A208007.

%H R. H. Hardin, <a href="/A208003/b208003.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) - 3*a(n-2) - 36*a(n-3) + 54*a(n-4) + 24*a(n-5) - 69*a(n-6) + 12*a(n-7) + 19*a(n-8) - 6*a(n-9) for n>10.

%F G.f.: x*(9 + 27*x - 238*x^2 - 223*x^3 + 1588*x^4 - 299*x^5 - 2044*x^6 + 767*x^7 + 603*x^8 - 234*x^9) / ((1 - x)*(1 + x)*(1 - 3*x + x^2)*(1 - x - x^2)*(1 - 2*x - 7*x^2 + 6*x^3)). - _Colin Barker_, Jun 26 2018

%e Some solutions for n=4:

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

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

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

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

%Y Cf. A208007.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 22 2012

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 August 19 03:10 EDT 2022. Contains 356216 sequences. (Running on oeis4.)