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Number of strings of numbers x(i=1..n) in 0..2 with sum i^2*x(i)^2 equal to n^2*4
1

%I #5 Mar 31 2012 12:35:58

%S 1,1,1,1,2,4,4,7,19,47,71,207,474,1077,2262,4729,9770,18932,39277,

%T 75259,142407,269217,504234,930683,1699058,3071779,5553557,9841969,

%U 17407209,30656831,53305283,92690067,159391413,274236367,467061289,794526219

%N Number of strings of numbers x(i=1..n) in 0..2 with sum i^2*x(i)^2 equal to n^2*4

%C Column 2 of A184240

%H R. H. Hardin, <a href="/A184233/b184233.txt">Table of n, a(n) for n = 1..75</a>

%e All solutions for n=5

%e ..0....0

%e ..0....0

%e ..0....2

%e ..0....2

%e ..2....0

%K nonn

%O 1,5

%A _R. H. Hardin_ Jan 10 2011