The number of subset sum

If we have that $S=\{1,2,3,4,5,6,7,8,9,10\}$,how to know the number of subset sum T from :S in which for every $x\in T$ and for every $2x\in S$ then: $2x \in T$

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sorry $x$ and $2*x$ are member of $T$?or ? –  dato datuashvili Aug 25 '12 at 21:28