A181207 - OEIS

%I #6 Mar 26 2018 09:54:57

%S 8,25,119,484,2117,9025,38936,167281,720083,3097600,13329209,57350329,

%T 246768392,1061782225,4568619071,19657722436,84582794333,363940725625,

%U 1565955363224,6737954403049,28991906279867,124745667481600

%N Number of n X 3 binary matrices with no two 1's adjacent diagonally or antidiagonally.

%C Column 3 of A181212.

%H R. H. Hardin, <a href="/A181207/b181207.txt">Table of n, a(n) for n=1..400</a>

%F Empirical: a(n) = 5*a(n-1) - 15*a(n-3) + 9*a(n-4).

%F Empirical g.f.: x*(8 - 15*x - 6*x^2 + 9*x^3) / ((1 - 5*x + 3*x^2)*(1 - 3*x^2)). - _Colin Barker_, Mar 26 2018

%Y Cf. A181212.

%K nonn

%O 1,1

%A _R. H. Hardin_, Oct 10 2010