# Is this possible 1

Number Theory Level pending

A positive integer with $$n$$ number of digits is called special ($$\overline{a_1a_2a_3a_4\dots a_{n}}$$), if $\overline{a_1a_2a_3a_4\dots a_{n}}+\overline{a_{n}a_{n-1}a_{n-2}\dots a_3a_2a_1}$ has only odd digits. ($$a_{n}\neq0$$.)

Which of the following could be the number of a special number's digits?

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