A206123 - OEIS

%I #5 Mar 31 2012 12:37:10

%S 558,3692,25340,201498,1622095,13475116,112183711,939358762,

%T 7868519564,65979083372,553282676669,4640551430206,38922156734987,

%U 326466825617358,2738306512199386,22968242764669498,192652048790354377

%N Number of (n+1)X4 0..2 arrays with every 2X2 subblock having nonzero determinant and having the same number of clockwise edge increases as its horizontal and vertical neighbors

%C Column 3 of A206128

%H R. H. Hardin, <a href="/A206123/b206123.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 6*a(n-1) +72*a(n-2) -352*a(n-3) -1842*a(n-4) +8483*a(n-5) +22782*a(n-6) -111329*a(n-7) -146524*a(n-8) +887675*a(n-9) +408834*a(n-10) -4451798*a(n-11) +555841*a(n-12) +13452774*a(n-13) -6983392*a(n-14) -21422904*a(n-15) +14294732*a(n-16) +15409732*a(n-17) -5535750*a(n-18) -954280*a(n-19) -7463176*a(n-20) -9198940*a(n-21) +4005472*a(n-22) +6349224*a(n-23) +1754032*a(n-24) -47088*a(n-25) -288592*a(n-26) -493376*a(n-27) -708032*a(n-28) -195872*a(n-29) +160192*a(n-30) +95296*a(n-31) +10752*a(n-32) -5376*a(n-33) for n>37

%e Some solutions for n=4

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

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

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

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

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

%K nonn

%O 1,1

%A _R. H. Hardin_ Feb 04 2012