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

 Hints (Greetings from The On-Line Encyclopedia of Integer Sequences!)
 A250640 Number of length n+1 0..2 arrays with the sum of the maximum of each adjacent pair multiplied by some arrangement of +-1 equal to zero. 1

%I #8 Nov 15 2018 12:50:15

%S 1,17,23,125,280,1061,2870,9495,27507,86149,255704,782393,2341381,

%T 7090347,21271463,64109181,192439733,578665211,1736971814,5217197093,

%U 15658051930,47004010481,141050402559,423295193635,1270100996174

%N Number of length n+1 0..2 arrays with the sum of the maximum of each adjacent pair multiplied by some arrangement of +-1 equal to zero.

%H R. H. Hardin, <a href="/A250640/b250640.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) - 3*a(n-2) - 42*a(n-3) + 71*a(n-4) + 56*a(n-5) - 192*a(n-6) + 80*a(n-7) + 77*a(n-8) - 64*a(n-9) + 12*a(n-10).

%F Empirical g.f.: x*(1 + 11*x - 76*x^2 + 80*x^3 + 242*x^4 - 541*x^5 + 201*x^6 + 239*x^7 - 192*x^8 + 36*x^9) / ((1 - x)*(1 - 2*x)*(1 + 2*x)*(1 - 3*x)*(1 - 3*x^2 + x^3)*(1 - 2*x - x^2 + x^3)). - _Colin Barker_, Nov 15 2018

%e Some solutions for n=6:

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

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

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

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

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

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

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

%Y Column 2 of A250646.

%K nonn

%O 1,2

%A _R. H. Hardin_, Nov 26 2014

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 9 01:17 EDT 2024. Contains 375759 sequences. (Running on oeis4.)