A251645 - OEIS

%I #7 Nov 30 2018 10:05:09

%S 376,448,738,1248,2382,4140,6978,13532,23574,39904,78046,136408,

%T 231290,455168,797254,1353500,2675622,4693960,7976098,15819328,

%U 27784502,47242988,93923158,165100664,280858818,559333552,983799526,1674143116

%N Number of (n+2) X (1+2) 0..3 arrays with no row, column, diagonal or antidiagonal in any 3 X 3 subblock summing to 0 2 4 5 7 or 9.

%H R. H. Hardin, <a href="/A251645/b251645.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = a(n-1) + 2*a(n-2) + 5*a(n-3) - 7*a(n-4) - 12*a(n-5) + 6*a(n-6) + 6*a(n-7) for n>14.

%F Empirical g.f.: 2*x*(188 + 36*x - 231*x^2 - 1133*x^3 + 25*x^4 + 1610*x^5 + 60*x^6 - 494*x^7 - 40*x^8 + 12*x^9 + 40*x^10 + 6*x^11 - 18*x^12 - 6*x^13) / ((1 - x)*(1 + x)*(1 - x - x^2)*(1 - 6*x^3)). - _Colin Barker_, Nov 30 2018

%e Some solutions for n=4:

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

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

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

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

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

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

%Y Column 1 of A251652.

%K nonn

%O 1,1

%A _R. H. Hardin_, Dec 06 2014