1 1 1 1 1nnR1 1 .

1 1 1 1

CCTV-1CCTV-124CCTV-1

Understanding the Context

... 11 1 1 .

1 1.

() () .

Although the number 1 used to be considered a prime number, it requires special treatment in so many definitions and applications involving primes greater than or equal to 2 that it is.

Key Insights

11 1.

11 11 111 1.

62332 161231123 1.