# Find sequence using sum of sequence (2)

Algebra Level pending

Let $$S_n$$ be the sum of a sequence $$\{a_n\}$$ from $$a_1$$ to $$a_n.$$ If $$\{a_n\}$$ is defined by $a_1 =2 \ , a_2=5 \ , \ a_n=3S_{n+1} -S_{n+2}-2S_n,$ what is $$a_{10}?$$

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