The rules are: the first number is 1, the second number is 2, and the third number is 1. Generally, write a line of 1, and then insert K 2 (k = 1, 2, 3,...) between the K 1 and K + 1 1 1 Question (1) is the number 2005 1 or 2? (2) What is the sum of the first 2005 numbers?

The odd number is one and the even number is two, so the number 2005 is 1
Every two items add up to 3, so the first 2004 numbers add up to 1200x3 = 3600, and then 1 equals 3601

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