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A188351 Number of arrangements of n+1 numbers x(i) in -2..2 with the sum of x(i)*x(i+1) equal to zero 1

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

%S 9,45,117,565,1953,9153,37269,173409,766869,3589357,16545861,78195505,

%T 368573829,1757922765,8394885777,40340645213,194259462205,

%U 938930726781,4547344031581,22077243778089,107366485176765,523060579628697

%N Number of arrangements of n+1 numbers x(i) in -2..2 with the sum of x(i)*x(i+1) equal to zero

%C Column 2 of A188358

%H R. H. Hardin, <a href="/A188351/b188351.txt">Table of n, a(n) for n = 1..200</a>

%e Some solutions for n=4

%e ..2...-1....1...-1...-2...-1....0....0....0...-1...-1....2....0...-2....1...-1

%e ..0...-2....2....2....1....1...-1....0...-2...-2...-1....0....0....2....2....1

%e ..0....1...-2...-1....0....1....0....0....0...-2...-2...-2....2....1....0....1

%e ..2....0...-2...-2...-2....2....1...-1...-2....2....1....1....0....1...-1....0

%e ..0...-1....1...-1...-1...-1....0....0....0...-1...-1....2....0....1....2...-1

%K nonn

%O 1,1

%A _R. H. Hardin_ Mar 28 2011

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Last modified February 23 18:28 EST 2024. Contains 370283 sequences. (Running on oeis4.)