A209549 - OEIS

%I #5 Mar 31 2012 12:37:29

%S 191,3051,46515,723636,11226644,174401424,2708892873,42079740150,

%T 653660484008,10153933128957,157730759876805,2450184099235301,

%U 38061075490701271,591239462480203821,9184293917133748801

%N 1/4 the number of (n+1)X5 0..3 arrays with every 2X2 subblock having exactly two distinct clockwise edge differences

%C Column 4 of A209553

%H R. H. Hardin, <a href="/A209549/b209549.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 26*a(n-1) -177*a(n-2) +43*a(n-3) +3477*a(n-4) -10179*a(n-5) -6160*a(n-6) +62922*a(n-7) -59442*a(n-8) -82557*a(n-9) +141262*a(n-10) +24872*a(n-11) -112175*a(n-12) +5660*a(n-13) +41275*a(n-14) -1936*a(n-15) -7049*a(n-16) -319*a(n-17) +400*a(n-18) +56*a(n-19) +2*a(n-20)

%e Some solutions for n=4

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 10 2012