A263434 - OEIS

%I #9 Jan 01 2019 20:13:38

%S 1,2,4,6,9,18,36,61,106,212,424,776,1449,2898,5796,11096,21486,42972,

%T 85944,168421,331914,663828,1327656,2630981,5227391,10454782,20909564,

%U 41648191,83053529,166107058,332214116,663226966,1324747321,2649494642

%N Number of (n+1) X (1+1) 0..4 arrays with each row and column divisible by 13, read as a base-5 number with top and left being the most significant digits.

%H R. H. Hardin, <a href="/A263434/b263434.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 2*a(n-1) + 9*a(n-4) - 18*a(n-5) - 14*a(n-8) + 28*a(n-9) + a(n-12) - 2*a(n-13).

%F Empirical g.f.: x*(1 - 2*x^3 - 12*x^4 + 7*x^7 + 25*x^8 - x^11 - 2*x^12) / ((1 - 2*x)*(1 + x^2 - 4*x^4 + x^6)*(1 - x^2 - 4*x^4 - x^6)). - _Colin Barker_, Jan 01 2019

%e All solutions for n=4:

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

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

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

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

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

%Y Column 1 of A263439.

%K nonn

%O 1,2

%A _R. H. Hardin_, Oct 18 2015