cp's OEIS Frontend

A183354 One quarter the number of nX2 1..4 arrays with no two neighbors of any element equal to each other.

%I A183354 #9 Jul 22 2025 08:51:11
%S A183354 4,36,144,576,2304,9216,36864,147456,589824,2359296,9437184,37748736,
%T A183354 150994944,603979776,2415919104,9663676416,38654705664,154618822656,
%U A183354 618475290624,2473901162496,9895604649984,39582418599936,158329674399744
%N A183354 One quarter the number of nX2 1..4 arrays with no two neighbors of any element equal to each other.
%C A183354 Column 2 of A183362
%H A183354 R. H. Hardin, <a href="/A183354/b183354.txt">Table of n, a(n) for n = 1..200</a>
%F A183354 Empirical: a(n)=4*a(n-1) = A002063(n-1) for n>2
%e A183354 Some solutions for 5X2 with a(1,1)=1
%e A183354 ..1..1....1..3....1..2....1..3....1..3....1..2....1..4....1..2....1..3....1..3
%e A183354 ..4..2....4..2....4..4....4..4....4..2....1..2....3..3....4..3....2..2....4..3
%e A183354 ..3..3....4..2....3..3....3..2....4..1....4..4....2..2....2..1....4..1....4..2
%e A183354 ..1..1....3..1....1..1....1..2....2..3....2..3....1..1....2..1....4..1....3..2
%e A183354 ..2..4....2..1....2..2....1..3....1..3....1..1....4..4....3..4....2..3....3..1
%K A183354 nonn
%O A183354 1,1
%A A183354 _R. H. Hardin_ Jan 04 2011