cp's OEIS Frontend

A250230 Number of length 3+1 0..n arrays with the sum of the cubes of adjacent differences multiplied by some arrangement of +-1 equal to zero.

%I A250230 #8 Nov 12 2018 14:38:52
%S A250230 8,27,52,89,132,187,248,321,400,491,588,697,812,939,1072,1217,1368,
%T A250230 1531,1700,1881,2068,2267,2472,2689,2912,3147,3388,3641,3900,4171,
%U A250230 4448,4737,5032,5339,5652,5977,6308,6651,7000,7361,7728,8107,8492,8889,9292,9707
%N A250230 Number of length 3+1 0..n arrays with the sum of the cubes of adjacent differences multiplied by some arrangement of +-1 equal to zero.
%H A250230 R. H. Hardin, <a href="/A250230/b250230.txt">Table of n, a(n) for n = 1..145</a>
%F A250230 Empirical: a(n) = 2*a(n-1) -2*a(n-3) +a(n-4).
%F A250230 Empirical for n mod 2 = 0: a(n) = (9/2)*n^2 + 4*n + 1.
%F A250230 Empirical for n mod 2 = 1: a(n) = (9/2)*n^2 + 4*n - (1/2).
%F A250230 Empirical g.f.: x*(8 + 11*x - 2*x^2 + x^3) / ((1 - x)^3*(1 + x)). - _Colin Barker_, Nov 12 2018
%e A250230 Some solutions for n=6:
%e A250230 ..2....1....5....0....0....4....1....6....5....1....2....1....4....5....2....3
%e A250230 ..2....4....5....4....6....4....3....3....5....4....5....3....4....5....2....2
%e A250230 ..4....1....0....0....6....3....3....0....4....4....2....3....2....6....6....1
%e A250230 ..6....1....5....0....0....4....1....0....3....1....2....5....0....5....2....1
%Y A250230 Row 3 of A250229.
%K A250230 nonn
%O A250230 1,1
%A A250230 _R. H. Hardin_, Nov 14 2014