A199144 - OEIS

%I #5 Mar 31 2012 12:36:35

%S 1,13,132,2453,42420,794416,14511531,268456338,4940928443,91146218920,

%T 1679743067872,30969409565822,570877041856787,10524153072061784,

%U 194006638767664141,3576453618832667684,65930406443303698229

%N Number of nX3 0..3 arrays with values 0..3 introduced in row major order and each element equal to one or two horizontal and vertical neighbors

%C Column 3 of A199149

%H R. H. Hardin, <a href="/A199144/b199144.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = 14*a(n-1) +120*a(n-2) -646*a(n-3) -1320*a(n-4) +3562*a(n-5) +12682*a(n-6) +1896*a(n-7) -76623*a(n-8) +36670*a(n-9) +19724*a(n-10) -245388*a(n-11) +53233*a(n-12) +2738818*a(n-13) -138967*a(n-14) -11411168*a(n-15) +3626519*a(n-16) +17979294*a(n-17) -10633666*a(n-18) -27553810*a(n-19) +19090457*a(n-20) +20077526*a(n-21) -32139160*a(n-22) +46609580*a(n-23) +115127457*a(n-24) +146403730*a(n-25) +50426678*a(n-26) -122760336*a(n-27) -143444310*a(n-28) -587979162*a(n-29) -679787397*a(n-30) -166474764*a(n-31) -212565465*a(n-32) +6372918*a(n-33) +256248603*a(n-34) +47278566*a(n-35) -708588*a(n-36) -12754584*a(n-37) for n>38

%e Some solutions for n=4

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

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

%e ..3..3..2....2..2..0....2..2..0....2..3..2....1..0..3....1..1..0....0..0..1

%e ..1..1..1....3..3..3....2..0..0....2..3..2....1..0..3....2..2..0....0..1..1

%K nonn

%O 1,2

%A _R. H. Hardin_ Nov 03 2011