A258965 - OEIS

%I #8 Dec 24 2018 08:30:12

%S 2040,1228,456,662,552,788,720,1046,1080,1570,1800,2618,3240,4714,

%T 6120,8906,11880,17290,23400,34058,46440,67594,92520,134666,184680,

%U 268810,369000,537098,737640,1073674,1474920,2146826,2949480,4293130,5898600

%N Number of (n+2) X (7+2) 0..1 arrays with no 3 X 3 subblock diagonal sum 0 and no antidiagonal sum 3 and no row sum 0 or 3 and no column sum 0 or 3.

%H R. H. Hardin, <a href="/A258965/b258965.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 3*a(n-2) - 2*a(n-4) for n>10.

%F Empirical g.f.: 2*x*(1020 + 614*x - 2832*x^2 - 1511*x^3 + 1632*x^4 + 629*x^5 - 12*x^6 + 3*x^7 + 12*x^8 + 4*x^9) / ((1 - x)*(1 + x)*(1 - 2*x^2)). - _Colin Barker_, Dec 24 2018

%e Some solutions for n=4:

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

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

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

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

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

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

%Y Column 7 of A258966.

%K nonn

%O 1,1

%A _R. H. Hardin_, Jun 15 2015