[tex] \it 2n+1|60 \Rightarrow 2n+1\in D_{60} \Rightarrow 2n+1\in \{1,\ 2,\ 3,\ 4,\ 5,\ 6,\ 10,\ 12,\ 15,\ 20,\ 30,\ 60\}|_{-1}\Rightarrow
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\Rightarrow 2x\in\{0,\ 1,\ 2,\ 3,\ 4, \ 5,\ 9,\ 11,\ 14,\ 19,\ 29,\ 59 \} \ \ \ \ \ \ (1)
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x\in\mathbb{N} \ \ \ \ \ \ (2)
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(1),\ (2) \Rightarrow x\in \{0,\ 1,\ 2,\ 7 \} [/tex]
