cp's OEIS Frontend

A258728 Number of length n+6 0..3 arrays with at most one downstep in every 6 consecutive neighbor pairs.

%I A258728 #6 Jul 23 2025 15:31:20
%S A258728 2592,5664,13720,35704,92548,228081,526672,1183616,2727288,6597449,
%T A258728 16454876,40863000,98379104,230053160,534172704,1260245516,3043544240,
%U A258728 7443617220,18093595536,43272115712,102190186552,241107878575
%N A258728 Number of length n+6 0..3 arrays with at most one downstep in every 6 consecutive neighbor pairs.
%C A258728 Column 6 of A258730
%H A258728 R. H. Hardin, <a href="/A258728/b258728.txt">Table of n, a(n) for n = 1..210</a>
%F A258728 Empirical: a(n) = 4*a(n-1) -6*a(n-2) +4*a(n-3) -a(n-4) +80*a(n-6) -204*a(n-7) +177*a(n-8) -52*a(n-9) -125*a(n-12) +184*a(n-13) -68*a(n-14) +10*a(n-18) -4*a(n-19)
%e A258728 Some solutions for n=4
%e A258728 ..0....3....0....3....3....1....0....2....0....0....1....0....0....3....3....1
%e A258728 ..3....3....0....3....3....2....1....0....3....2....1....2....2....3....1....2
%e A258728 ..0....0....2....0....1....3....0....1....3....0....0....2....0....1....1....0
%e A258728 ..0....2....3....0....1....3....0....2....3....0....0....2....0....1....2....1
%e A258728 ..0....2....0....0....2....1....1....3....3....1....0....2....1....1....3....2
%e A258728 ..0....2....0....1....2....1....2....3....3....1....3....1....2....1....3....2
%e A258728 ..1....3....0....2....2....1....2....3....3....1....3....1....2....1....3....3
%e A258728 ..3....3....2....2....3....1....3....3....0....1....3....1....3....1....0....3
%e A258728 ..2....3....3....0....1....2....2....1....1....2....0....1....3....3....1....0
%e A258728 ..2....3....3....1....3....3....3....3....2....2....1....1....0....1....1....2
%Y A258728 Cf. A258730
%K A258728 nonn
%O A258728 1,1
%A A258728 _R. H. Hardin_, Jun 08 2015