A237672 - OEIS

%I #7 Jan 16 2022 00:35:02

%S 256,1564,9647,63000,412120,2668500,17280632,112196812,729345568,

%T 4730716616,30705881416,199250972104,1294118583944,8396039853104,

%U 54516655728608,353723940339776,2297049424994128,14903574260972720

%N Number of (n+1) X (1+1) 0..3 arrays with the maximum plus the upper median plus the minimum of every 2 X 2 subblock differing from its horizontal and vertical neighbors by exactly one.

%C Column 1 of A237677.

%H R. H. Hardin, <a href="/A237672/b237672.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 1464*a(n-4) +21444*a(n-6) -217012*a(n-8) -5585804*a(n-10) -12617424*a(n-12) +351921344*a(n-14) +2542892384*a(n-16) +1019240768*a(n-18) -42797024832*a(n-20) -123435815936*a(n-22) +85546957824*a(n-24) +742456289792*a(n-26) +481891066880*a(n-28) -1227137187840*a(n-30) -1305858437120*a(n-32) +134355173376*a(n-34) +344315133952*a(n-36) -1108344832*a(n-38) -26916945920*a(n-40) -3468689408*a(n-42) -369098752*a(n-44) for n>45.

%e Some solutions for n=4

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

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

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

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

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

%Y Cf. A237677.

%K nonn

%O 1,1

%A _R. H. Hardin_, Feb 11 2014