|
%I #10 Nov 12 2018 15:38:36
%S 2,8,8,24,42,104,212,464,950,1968,3984,8072,16226,32600,65324,130848,
%T 261870,524000,1048232,2096792,4193882,8388168,16776708,33553904,
%U 67108262,134217104,268434752,536870184,1073741010,2147482808,4294966364
%N Number of length n+2 0..1 arrays with the sum of second differences squared multiplied by some arrangement of +-1 equal to zero.
%H R. H. Hardin, <a href="/A250313/b250313.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 3*a(n-1) - 6*a(n-3) + 3*a(n-4) + 3*a(n-5) - 2*a(n-6).
%F Empirical g.f.: 2*x*(1 + x - 8*x^2 + 6*x^3 + 6*x^4 - 2*x^5) / ((1 - x)^3*(1 + x)^2*(1 - 2*x)). - _Colin Barker_, Nov 12 2018
%e Some solutions for n=6:
%e ..1....0....0....0....1....0....0....1....1....0....1....0....0....1....1....0
%e ..1....0....0....1....1....0....1....1....0....0....0....1....1....0....0....0
%e ..0....0....0....0....1....1....0....0....1....0....0....0....0....1....1....1
%e ..0....0....1....0....0....1....1....1....0....1....1....1....0....1....1....1
%e ..1....1....1....0....0....1....0....0....1....1....0....1....1....0....0....1
%e ..0....0....1....0....1....1....0....0....0....1....0....1....1....0....0....0
%e ..0....1....0....1....1....1....1....1....1....1....0....1....0....1....0....1
%e ..0....1....0....0....1....1....0....1....0....1....1....0....1....0....1....1
%Y Column 1 of A250320.
%K nonn
%O 1,1
%A _R. H. Hardin_, Nov 18 2014
| 