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A199914 Number of -n..n arrays x(0..6) of 7 elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2) 1

%I #5 Mar 31 2012 12:36:37

%S 56,654,5206,24864,77874,216530,518560,1071202,2114394,3876376,

%T 6593960,10975656,17458840,26545266,39896954,58112992,82129122,

%U 115325122,158200672,212380574,284094678,373133880,482198944,621972384,790417208

%N Number of -n..n arrays x(0..6) of 7 elements with zero sum, and adjacent elements not equal modulo three (with -1 modulo 3 = 2)

%C Row 7 of A199909

%H R. H. Hardin, <a href="/A199914/b199914.txt">Table of n, a(n) for n = 1..200</a>

%F Empirical: a(n) = a(n-1) +6*a(n-3) -6*a(n-4) -15*a(n-6) +15*a(n-7) +20*a(n-9) -20*a(n-10) -15*a(n-12) +15*a(n-13) +6*a(n-15) -6*a(n-16) -a(n-18) +a(n-19)

%e Some solutions for n=6

%e .-5...-3...-3....3...-6....3...-6....3....0...-3....4...-6....4...-5...-6...-3

%e .-3...-1....5....1...-5...-2....2...-5....5....4...-4....5...-3...-3...-1...-1

%e ..2...-5....4....0....6...-4...-5....2...-3...-4...-6...-5....2....2....6....0

%e ..3....2...-3....1....2....3....5...-3....4....6...-1....6....3....3....1...-2

%e ..4....6....1....0....0....2....3....1...-1...-1....6...-1....4....1....6....5

%e .-1...-5...-6....1....5...-5....1....5...-6....4....4...-5...-6....3...-5....4

%e ..0....6....2...-6...-2....3....0...-3....1...-6...-3....6...-4...-1...-1...-3

%K nonn

%O 1,1

%A _R. H. Hardin_ Nov 11 2011

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Last modified March 2 01:29 EST 2024. Contains 370447 sequences. (Running on oeis4.)