|
%I #10 Jun 10 2018 20:46:43
%S 342,38,35,40,48,61,82,116,171,260,404,637,1014,1624,2611,4208,6792,
%T 10973,17738,28684,46395,75052,121420,196445,317838,514256,832067,
%U 1346296,2178336,3524605,5702914,9227492,14930379,24157844,39088196
%N Number of (n+2) X 7 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically, diagonally or antidiagonally exactly three ways, and new values 0..1 introduced in row major order.
%C Column 5 of A204754.
%H R. H. Hardin, <a href="/A204751/b204751.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 2*a(n-1) - a(n-3) for n > 5.
%F Empirical g.f.: x*(342 - 646*x - 41*x^2 + 312*x^3 + 6*x^4) / ((1 - x)*(1 - x - x^2)). - _Colin Barker_, Jun 10 2018
%e Some solutions for n=3:
%e 0 1 0 1 0 0 1 0 0 1 1 1 0 0 0 0 1 0 1 0 1
%e 0 1 0 1 0 0 1 0 0 0 1 1 1 0 0 0 1 0 1 0 1
%e 0 1 0 1 0 0 1 1 0 0 0 1 1 1 0 0 1 0 1 0 1
%e 0 1 0 1 0 0 1 1 1 0 0 0 1 1 0 0 1 0 1 0 1
%e 0 1 0 1 0 0 1 1 1 1 0 0 0 1 0 0 1 0 1 0 1
%Y Cf. A204754.
%K nonn
%O 1,1
%A _R. H. Hardin_, Jan 18 2012
|
