A210118 - OEIS

A210118

Number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having two or four distinct values, and new values 0..3 introduced in row major order.

%I #11 Jul 14 2018 15:34:38

%S 8,44,265,1702,11369,77642,536581,3731446,26032433,181914722,

%T 1272290749,8902073710,62300406761,436052596634,3052189205941,

%U 21364687028710,149550539021345,1046845687784786,7327891018040365,51295134566193886

%N Number of (n+1) X 2 0..3 arrays with every 2 X 2 subblock having two or four distinct values, and new values 0..3 introduced in row major order.

%C Column 1 of A210125.

%H R. H. Hardin, <a href="/A210118/b210118.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 10*a(n-1) - 19*a(n-2) - 14*a(n-3).

%F Empirical g.f.: x*(8 - 36*x - 23*x^2) / ((1 - 7*x)*(1 - 3*x - 2*x^2)). - _Colin Barker_, Jul 14 2018

%e Some solutions for n=4:

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

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

%e 2 3 0 0 0 1 1 1 0 0 1 1 0 1 1 0 2 3 0 0

%e 2 3 0 1 1 1 2 1 2 2 1 2 1 0 0 1 1 0 0 1

%e 3 2 0 0 0 0 2 2 1 1 2 1 0 0 0 0 0 0 1 1

%Y Cf. A210125.

%K nonn

%O 1,1

%A _R. H. Hardin_, Mar 17 2012