## poj3292

maksyuki 发表于 oj 分类，标签:

Semi-prime H-numbers

An H-number is a positive number which is one more than a multiple of four: 1, 5, 9, 13, 17, 21,... are the H-numbers. For this problem we pretend that these are the only numbers. The H-numbers are closed under multiplication.T >>继续阅读

## poj2689

maksyuki 发表于 oj 分类，标签:

Prime Distance

The branch of mathematics called number theory is about properties of numbers. One of the areas that has captured the interest of number theoreticians for thousands of years is the question of primality >>继续阅读

## hdu2521

maksyuki 发表于 oj 分类，标签:

Problem Description

Input

## hdu2098

maksyuki 发表于 oj 分类，标签:

Problem Description

Input

## uva10533

maksyuki 发表于 oj 分类，标签:

Digit Primes

A prime number is a positive number, which is divisible by exactly two different integers. A digit prime is a prime number whose sum of digits is also prime. For example the prime number 41 is a digit prime

because 4+1=5 and 5 is a p >>继续阅读

## uva10168

maksyuki 发表于 oj 分类，标签:

Euler proved in one of his classic theorems that prime numbers are infinite in number. But can every number be expressed as a summation of four positive primes? I don’t know the answer. May be you can help!!! I want your solution to be very efficient >>继续阅读