cp's OEIS Frontend

A200058 Number of -n..n arrays x(0..3) of 4 elements with zero sum and elements alternately strictly increasing and strictly decreasing.

%I A200058 #8 May 17 2018 10:59:55
%S A200058 4,26,78,172,324,546,850,1252,1764,2398,3170,4092,5176,6438,7890,9544,
%T A200058 11416,13518,15862,18464,21336,24490,27942,31704,35788,40210,44982,
%U A200058 50116,55628,61530,67834,74556,81708,89302,97354,105876,114880,124382,134394
%N A200058 Number of -n..n arrays x(0..3) of 4 elements with zero sum and elements alternately strictly increasing and strictly decreasing.
%C A200058 Row 4 of A200057.
%H A200058 R. H. Hardin, <a href="/A200058/b200058.txt">Table of n, a(n) for n = 1..200</a>
%F A200058 Empirical: a(n) = 3*a(n-1) -3*a(n-2) +2*a(n-3) -3*a(n-4) +3*a(n-5) -a(n-6).
%F A200058 Empirical g.f.: 2*x*(2 + x + x^2)*(1 + 3*x + x^2) / ((1 - x)^4*(1 + x + x^2)). - _Colin Barker_, May 17 2018
%e A200058 Some solutions for n=6:
%e A200058 ..2....6...-2....5....6...-2....2...-3....5....2....1....0....3....2....1....6
%e A200058 ..5...-6...-3...-2...-4...-3...-4...-4...-5....0....3...-5...-3...-1...-4...-3
%e A200058 .-5....3....5....1....1....3....6....6....6....1...-3....5....1....0....5....0
%e A200058 .-2...-3....0...-4...-3....2...-4....1...-6...-3...-1....0...-1...-1...-2...-3
%Y A200058 Cf. A200057.
%K A200058 nonn
%O A200058 1,1
%A A200058 _R. H. Hardin_, Nov 13 2011