%I #5 Mar 31 2012 12:36:45
%S 1,9,25,313,1401,15681,90609,909945,6105913,57290209,421304049,
%T 3799765201,29595440785,261111392985,2109792275145,18400232046585,
%U 152275971653625,1320864136716225,11107129707193809,96160509723165393
%N Number of arrays of n integers in -4..4 with sum zero and equal numbers of elements greater than zero and less than zero
%C Column 4 of A201811
%H R. H. Hardin, <a href="/A201807/b201807.txt">Table of n, a(n) for n = 1..210</a>
%e Some solutions for n=7
%e .-3....0...-1....4...-2...-4....4...-2....4....4...-3....2....4...-4....1....2
%e ..0....2....2...-4...-2...-4...-4...-1....0....0....0...-4....0...-4...-3...-3
%e .-4...-4....1...-4....2....4...-3...-4...-3...-4...-2....3....2...-2....1...-4
%e ..2...-2....0....0....2....0....0....2...-2....1....4...-3...-4....0...-1....0
%e .-2....4....3...-2...-1....3...-2....4....3...-3...-4....4....4....2....4...-2
%e ..4....1...-1....3....1...-3....4....0....1...-2....3...-2...-2....4...-2....4
%e ..3...-1...-4....3....0....4....1....1...-3....4....2....0...-4....4....0....3
%K nonn
%O 1,2
%A _R. H. Hardin_ Dec 05 2011