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How many arrangements of the numbers $1, 2, 3, \dots, 7$ are there where the sum of any two adjacent numbers is odd?

Guest Mar 22, 2019

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Best Answer

$\text{the first number must be odd}\\ 4 \cdot 3 \cdot 3 \cdot 2 \cdot 2 = 144\\$

Rom Mar 22, 2019

Rom · Answer 1 · 2019-03-22T03:28:01

$\text{the first number must be odd}\\ 4 \cdot 3 \cdot 3 \cdot 2 \cdot 2 = 144\\$

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