cp's OEIS Frontend

A267472 Number of length-4 0..n arrays with no following elements larger than the first repeated value.

%I A267472 #7 Feb 05 2018 09:36:15
%S A267472 12,62,204,515,1096,2072,3592,5829,8980,13266,18932,26247,35504,47020,
%T A267472 61136,78217,98652,122854,151260,184331,222552,266432,316504,373325,
%U A267472 437476,509562,590212,680079,779840,890196,1011872,1145617,1292204
%N A267472 Number of length-4 0..n arrays with no following elements larger than the first repeated value.
%C A267472 Row 4 of A267471.
%H A267472 R. H. Hardin, <a href="/A267472/b267472.txt">Table of n, a(n) for n = 1..210</a>
%F A267472 Empirical: a(n) = n^4 + (17/6)*n^3 + 4*n^2 + (19/6)*n + 1.
%F A267472 Conjectures from _Colin Barker_, Feb 05 2018: (Start)
%F A267472 G.f.: x*(12 + 2*x + 14*x^2 - 5*x^3 + x^4) / (1 - x)^5.
%F A267472 a(n) = 5*a(n-1) - 10*a(n-2) + 10*a(n-3) - 5*a(n-4) + a(n-5) for n>5.
%F A267472 (End)
%e A267472 Some solutions for n=7:
%e A267472 ..2....1....5....5....0....2....5....6....3....4....0....0....3....3....2....3
%e A267472 ..6....5....2....5....6....4....2....0....6....5....6....3....0....2....5....4
%e A267472 ..0....2....3....0....3....1....0....4....3....1....4....0....5....5....6....7
%e A267472 ..1....7....1....0....7....1....3....7....5....0....3....0....2....5....4....4
%Y A267472 Cf. A267471.
%K A267472 nonn
%O A267472 1,1
%A A267472 _R. H. Hardin_, Jan 15 2016