A180374 - OEIS

A180374

1/120 the number of n X 3 arrays of integers in 1..6 with no element or any of its neighbors having the same value.

%I #10 Mar 26 2018 09:54:38

%S 1,21,156,1236,9552,74568,579792,4515312,35141952,273573984,

%T 2129509056,16576843584,129037857024,1004466036864,7819018652928,

%U 60865289156352,473791157511168,3688113552987648,28709232900123648,223480124314162176

%N 1/120 the number of n X 3 arrays of integers in 1..6 with no element or any of its neighbors having the same value.

%H R. H. Hardin, <a href="/A180374/b180374.txt">Table of n, a(n) for n=1..99</a>

%F Empirical (for n>=5): a(n) = 6*a(n-1) + 18*a(n-2) - 32*a(n-3). - _Vaclav Kotesovec_, Nov 27 2012

%F Empirical g.f.: x*(1 + 15*x + 12*x^2 - 46*x^3) / (1 - 6*x - 18*x^2 + 32*x^3). - _Colin Barker_, Mar 26 2018

%K nonn

%O 1,2

%A _R. H. Hardin_, Sep 01 2010