A257061 - OEIS

%I #8 Dec 20 2018 16:09:55

%S 5,27,141,738,3866,20249,106056,555483,2909419,15238479,79813616,

%T 418034724,2189514005,11467878868,60064583029,314596463387,

%U 1647741976789,8630273820766,45202238742834,236752903766237,1240025693431636

%N Number of length n 1..(7+1) arrays with every leading partial sum divisible by 2 or 3.

%H R. H. Hardin, <a href="/A257061/b257061.txt">Table of n, a(n) for n = 1..210</a>

%F Empirical: a(n) = 4*a(n-1) + 5*a(n-2) + 7*a(n-3) + 4*a(n-4).

%F Empirical g.f.: x*(5 + 7*x + 8*x^2 + 4*x^3) / (1 - 4*x - 5*x^2 - 7*x^3 - 4*x^4). - _Colin Barker_, Dec 20 2018

%e Some solutions for n=4:

%e ..4....6....4....8....3....6....6....6....2....2....2....3....4....4....3....3

%e ..8....8....6....8....5....2....8....3....2....1....7....3....8....2....7....5

%e ..4....1....5....6....8....4....2....1....4....7....6....8....6....6....5....8

%e ..6....1....7....5....2....3....4....4....6....4....1....1....3....3....1....4

%Y Column 7 of A257062.

%K nonn

%O 1,1

%A _R. H. Hardin_, Apr 15 2015