山寨原題: 數軸上的每一個奇數,無一例外地都是某個梅森數(2^n-1)的因子嗎?
你這個問題隻要學過抽象代數的人都能證明。用一下Euler定理就行。
if A and B are co-prime positive integers (i.e. gcd(A,B) = 1), then there exists a positive integer n, such that A^n = 1 (mod B).
也就是說 B is a factor of A^n - 1. Your question is a special case for A=2,B=odd number.
Another example, 81=3^4, n=2x3^3=54, 81 | 2^54 - 1.
Another example 117 = 3^2 x 13, n=lcm(2x3, 12) = 12, 117 | 2^12 - 1
Note: such n is not unique. for example 17 | 2^16 -1, 17 | 2^8 - 1.
The beauty of mathematics is existence + uniqueness.