The OEIS is supported by the many generous donors to the OEIS Foundation.
%I #8 Dec 16 2017 15:13:42
%S 1,3,5,19,45,129,345,1031,2969,8803,25791,76285,225047,667807,1984599,
%T 5918017,17672419,52880691,158447783,475463579,1428412619,4296219727,
%U 12934516047,38978330199,117561661847,354857238103,1071910795169
%N Number of zero-sum -2..2 arrays of n elements with first and second differences also in -2..2
%C Column 2 of A201873
%H R. H. Hardin, <a href="/A201867/b201867.txt">Table of n, a(n) for n = 1..210</a>
%H Wolfdieter Lang, <a href="https://arxiv.org/abs/1708.01421">On Generating functions of Diagonals Sequences of Sheffer and Riordan Number Triangles</a>, arXiv:1708.01421 [math.NT], August 2017.
%e Some solutions for n=10
%e .-1....1...-1....2...-1...-1....1....2....2....0...-2...-2...-2....2...-2...-2
%e .-1....2...-2....2....0...-1....1....2....2...-1...-2...-2...-1....1....0...-2
%e ..1....1...-1....2...-1...-1....0....2....1....0...-1....0....0...-1....0....0
%e ..1....0....0....1...-1...-2...-1....0....1....2....0....2...-1...-2....1....0
%e ..0...-1....1....0...-1...-1...-1...-1...-1....2....0....2...-1...-2....1....0
%e .-1...-1....0....0....0....0....0....0...-1....1....0....0...-1....0....1....0
%e ..0....0....1...-2....0....1....1...-1....0....0....1...-1....1....1....1....0
%e ..0...-1....1...-2....1....2....0...-1....0...-2....1....0....2....0...-1....1
%e ..0....0....1...-2....2....2...-1...-1...-2...-2....1....0....1....1...-1....2
%e ..1...-1....0...-1....1....1....0...-2...-2....0....2....1....2....0....0....1
%K nonn
%O 1,2
%A _R. H. Hardin_ Dec 06 2011