Difference between revisions of "2004 AIME I Problems/Problem 6"
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== Problem == | == Problem == | ||
| − | An integer is called snakelike if its decimal representation <math> a_1a_2a_3\cdots a_k </math> satisfies <math> a_i<a_{i+1} </math> if <math> i </math> is odd and <math> a_i>a_{i+1} </math> if <math> i </math> is even. How many snakelike integers between 1000 and 9999 have four distinct digits? | + | An integer is called snakelike if its decimal representation <math> a_1a_2a_3\cdots a_k </math> satisfies <math> a_i<a_{i+1} </math> if <math> i </math> is [[odd integer | odd]] and <math> a_i>a_{i+1} </math> if <math> i </math> is [[even integer | even]]. How many snakelike integers between 1000 and 9999 have four distinct digits? |
== Solution == | == Solution == | ||
satisfies 
if 
is 
if 
