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A199709 Number of -n..n arrays x(0..6) of 7 elements with zero sum and no two neighbors equal.

%I A199709 #12 Jul 22 2025 13:23:18
%S A199709 56,2642,27854,149942,559028,1643204,4099204,9059092,18251656,
%T A199709 34171380,60292468,101279218,163252890,254042820,383508158,563826638,
%U A199709 809873706,1139548482,1574209250,2139036592,2863528108,3781894246,4933615190
%N A199709 Number of -n..n arrays x(0..6) of 7 elements with zero sum and no two neighbors equal.
%C A199709 Row 7 of A199704
%H A199709 R. H. Hardin, <a href="/A199709/b199709.txt">Table of n, a(n) for n = 1..200</a>
%F A199709 Empirical: a(n)=2*a(n-1)-a(n-3)-a(n-5)+a(n-6)-2*a(n-7)+2*a(n-8)+a(n-9)-a(n-13)-2*a(n-14)+2*a(n-15)-a(n-16)+a(n-17)+a(n-19)-2*a(n-21)+a(n-22)
%e A199709 Some solutions for n=5
%e A199709 .-4....2...-5....0...-4...-4...-5....0....1....1....0...-5....2...-5....1....2
%e A199709 ..1...-5....2....2....1....2....1...-5....0...-5...-4....0...-5....0...-4....1
%e A199709 ..5....3...-1...-2....4...-1....4...-3....3....1....4....4...-4....3...-3....2
%e A199709 ..4....4....5....4...-4....3....2....1...-1....3...-1...-5....4....1....2...-1
%e A199709 .-1....3...-3....2....4...-1....5....2...-2...-2...-2...-1....2....3....5...-5
%e A199709 .-4...-4...-2...-5....1....2...-5....1....3...-1....5....4...-1...-2....0...-1
%e A199709 .-1...-3....4...-1...-2...-1...-2....4...-4....3...-2....3....2....0...-1....2
%K A199709 nonn
%O A199709 1,1
%A A199709 _R. H. Hardin_ Nov 09 2011