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A199908 Number of -7..7 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2).

%I A199908 #7 Jun 02 2025 05:25:27
%S A199908 1,10,114,680,6064,62776,518560,4854740,47329800,436295060,4163000530,
%T A199908 40224691008,383919683336,3702037559404,35864644194258,
%U A199908 346836775041832,3366637367524806,32752033994479420,318790073410891420
%N A199908 Number of -7..7 arrays x(0..n-1) of n elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2).
%C A199908 Column 7 of A199909
%H A199908 R. H. Hardin, <a href="/A199908/b199908.txt">Table of n, a(n) for n = 1..200</a>
%e A199908 Some solutions for n=6
%e A199908 .-2...-1....2...-7...-5...-2...-2...-2...-4...-5...-2...-4...-2...-3....4....0
%e A199908 .-1....7....7....1...-6....5...-1...-1....1...-3....5...-3....3...-7....3...-7
%e A199908 ..4....0....5....2....5...-3....6...-6...-6....5....6....7....4....1...-1....4
%e A199908 .-1...-5...-5....6...-5....2...-7...-4....4...-5....2....5...-3....6...-5....2
%e A199908 ..1....3...-7....1....6...-2....0....7....0....3...-5...-2....4...-4...-4...-5
%e A199908 .-1...-4...-2...-3....5....0....4....6....5....5...-6...-3...-6....7....3....6
%K A199908 nonn
%O A199908 1,2
%A A199908 _R. H. Hardin_ Nov 11 2011