A231026 - OEIS

%I #4 Nov 03 2013 06:15:46

%S 0,12,60,1074,12400,162288,2049324,26149710,332659424,4235875140,

%T 53922195170,686478044994,8739276731656,111257016629792,

%U 1416375531056864,18031410076232628,229551897159731062,2922349174918753464

%N Number of nX3 0..2 arrays x(i,j) with each element horizontally, vertically or antidiagonally next to at least one element with value (x(i,j)+1) mod 3 and at least one element with value (x(i,j)-1) mod 3, and upper left element zero

%C Column 3 of A231031

%H R. H. Hardin, <a href="/A231026/b231026.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 12*a(n-1) +24*a(n-2) -198*a(n-3) +143*a(n-4) -39*a(n-5) -1072*a(n-6) +15046*a(n-7) -50039*a(n-8) -76233*a(n-9) +310401*a(n-10) -79074*a(n-11) -282050*a(n-12) +99013*a(n-13) +127303*a(n-14) -86657*a(n-15) +1974*a(n-16) +55618*a(n-17) -23205*a(n-18) -15363*a(n-19) +9601*a(n-20) -2560*a(n-21) -2599*a(n-22) +1807*a(n-23) +98*a(n-24) -123*a(n-25) +124*a(n-26) -a(n-27) -14*a(n-28)

%e Some solutions for n=3

%e ..0..1..0....0..1..0....0..1..0....0..1..0....0..1..0....0..1..2....0..2..0

%e ..2..1..2....2..2..2....2..0..2....2..2..1....2..0..2....2..0..2....1..1..0

%e ..1..0..1....0..1..0....0..1..0....1..0..2....1..0..1....0..1..0....0..2..1

%K nonn

%O 1,2

%A _R. H. Hardin_, Nov 03 2013