# 素数筛 #
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Sum of Consecutive Prime Numbers（POJ2739）
题意 给定一个1~n之间的数，问由连续素数凑成该数的的方案有几种，比如：53 = 53， 53 = 5 + 7 + 11 + 13 + 17，那么方案数就是2. 分析 注意这里暴力的枚举方法。 AC代码 #incl...
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Semi-prime H-numbers
题目 This problem is based on an exercise of David Hilbert, who pedagogically suggested that one study the theory of 4n+1...
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X-factor Chains
题目 Given a positive integer X, an X-factor chain of length m is a sequence of integers, 1 = X0, X1, X2, …, Xm = X...
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Prime Number
题目 Write a program which reads an integer n and prints the number of prime numbers which are less than or equal to n. A...