A251374 - OEIS

%I #9 Nov 29 2018 10:37:16

%S 124,1048,9124,80296,709396,6276040,55551652,491795368,4354105588,

%T 38549885704,341311285636,3021895319272,26755225413460,

%U 236885220581704,2097332909359972,18569354042228776,164409242545738420

%N Number of (n+1) X (1+1) 0..3 arrays with every 2 X 2 subblock summing to 5 6 or 7.

%H R. H. Hardin, <a href="/A251374/b251374.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 10*a(n-1) - 3*a(n-2) - 66*a(n-3) + 24*a(n-4).

%F Empirical g.f.: 4*x*(31 - 48*x - 246*x^2 + 96*x^3) / (1 - 10*x + 3*x^2 + 66*x^3 - 24*x^4). - _Colin Barker_, Nov 29 2018

%e Some solutions for n=4:

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

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

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

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

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

%Y Column 1 of A251381.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 01 2014