A251235 - OEIS

%I #10 Aug 10 2015 23:45:37

%S 27714,42850,71322,129378,250622,514950,1112526,2511890,5892002,

%T 14279706,35575142,90692606,235679686,622362410,1666024058,4512772642,

%U 12352459294,34135460774,95175625390,267630015058,758790404898,2168797835866

%N Number of (n+1) X (7+1) 0..3 arrays with every 2 X 2 subblock summing to 6 and no 2 X 2 subblock having exactly two nonzero entries.

%C Column 7 of A251236.

%H R. H. Hardin, <a href="/A251235/b251235.txt">Table of n, a(n) for n = 1..112</a>

%F Empirical: a(n) = 13*a(n-1) -63*a(n-2) +122*a(n-3) +13*a(n-4) -371*a(n-5) +317*a(n-6) +308*a(n-7) -370*a(n-8) -144*a(n-9) +128*a(n-10) +48*a(n-11).

%e Some solutions for n=4:

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

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

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

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

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

%Y Cf. A251236.

%K nonn

%O 1,1

%A _R. H. Hardin_, Nov 30 2014