A207238 - OEIS

%I #5 Mar 31 2012 12:37:16

%S 9,81,283,987,3866,13494,44730,150608,498551,1615388,5213924,16743300,

%T 53330410,169085209,534330613,1682097877,5278749205,16525845242,

%U 51617974464,160893899363,500630178086,1555278833939,4824719777577

%N Number of nX4 0..1 arrays avoiding 0 0 0 and 0 1 1 horizontally and 0 0 1 and 0 1 0 vertically

%C Column 4 of A207242

%H R. H. Hardin, <a href="/A207238/b207238.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 5*a(n-1) -6*a(n-2) +24*a(n-3) -87*a(n-4) +24*a(n-5) -155*a(n-6) +534*a(n-7) +401*a(n-8) +731*a(n-9) -1499*a(n-10) -2615*a(n-11) -3148*a(n-12) +1796*a(n-13) +6170*a(n-14) +7794*a(n-15) +630*a(n-16) -7609*a(n-17) -10518*a(n-18) -4095*a(n-19) +4874*a(n-20) +8369*a(n-21) +4506*a(n-22) -1299*a(n-23) -3802*a(n-24) -2467*a(n-25) -86*a(n-26) +905*a(n-27) +680*a(n-28) +144*a(n-29) -96*a(n-30) -82*a(n-31) -27*a(n-32) -a(n-33) +4*a(n-34) +2*a(n-35)

%e Some solutions for n=4

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 16 2012