A209370 - OEIS

%I #5 Mar 31 2012 12:37:28

%S 35,129,242,968,3698,14112,54450,208658,798848,3065288,11761250,

%T 45106002,172980000,663426738,2544555122,9759442050,37430668832,

%U 143559037778,550601290962,2111759107200,8099354578322,31063907847200,119141222480000

%N Number of nX4 1..3 arrays with no element with value z exactly a city block distance of z from another element with value z

%C Column 4 of A209374

%H R. H. Hardin, <a href="/A209370/b209370.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) +4*a(n-2) +13*a(n-3) +38*a(n-4) +56*a(n-5) +20*a(n-6) -107*a(n-7) -179*a(n-8) -5*a(n-9) +123*a(n-10) -11*a(n-11) -105*a(n-12) -74*a(n-13) -16*a(n-14) +25*a(n-15) +19*a(n-16) +6*a(n-17) +3*a(n-18) +2*a(n-20) -a(n-21) for n>23

%e Some solutions for n=5

%e ..2..1..3..1....2..2..1..3....1..2..1..3....1..3..1..2....2..2..3..1

%e ..1..3..1..3....3..1..3..2....3..1..3..1....2..2..3..1....1..3..1..2

%e ..3..1..2..1....1..3..1..2....2..3..1..3....1..3..1..3....3..1..3..1

%e ..2..3..1..3....3..2..3..1....2..1..3..2....3..1..2..1....1..2..1..3

%e ..2..1..3..2....1..2..1..3....1..3..1..3....1..3..1..3....3..1..3..2

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 07 2012