|
%I #12 Jun 15 2018 11:59:58
%S 1,4,17,120,884,6558,48680,361422,2683328,19922214,147910952,
%T 1098154590,8153170064,60532632918,449420225720,3336688521102,
%U 24773006668448,183925426722054,1365541253642312,10138363949208510,75271562311604144
%N Number of n X 2 0..4 arrays with no element equal to another within two positions in the same row or column, and new values 0..4 introduced in row major order.
%C Column 2 of A206359.
%H R. H. Hardin, <a href="/A206353/b206353.txt">Table of n, a(n) for n = 1..210</a>
%F Empirical: a(n) = 6*a(n-1) + 13*a(n-2) - 18*a(n-3) for n>5.
%F Empirical g.f.: x*(1 - 2*x - 20*x^2 - 16*x^3 + 15*x^4) / ((1 - x)*(1 - 5*x - 18*x^2)). - _Colin Barker_, Jun 15 2018
%e Some solutions for n=4:
%e ..0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1....0..1
%e ..1..0....1..2....2..3....1..0....1..2....1..0....2..3....1..2....2..3....1..0
%e ..2..3....2..0....3..2....2..3....3..4....2..3....1..4....2..3....4..2....2..3
%e ..3..4....3..4....4..0....4..1....2..3....3..1....0..1....3..0....0..1....0..4
%Y Cf. A206359.
%K nonn
%O 1,2
%A _R. H. Hardin_, Feb 06 2012
| 