AoPS Wiki:Problem of the Day/July 6, 2011
Find the sum $1+11+\cdots+\underbrace{111\cdots 111}_{n}}$ (Error compiling LaTeX. Unknown error_msg).
Find the sum $1+11+\cdots+\underbrace{111\cdots 111}_{n}}$ (Error compiling LaTeX. Unknown error_msg).
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