摘要： Coin partitions Let p(n) represent the number of different ways in which n coins can be separated into piles. For example, five coins can separated into piles in exactly seven different ways, so p(5)=... 阅读全文

摘要： 原题：Prime summationsIt is possible to write ten as the sum of primes in exactly five different ways:7 + 35 + 55 + 3 + 23 + 3 + 2 + 22 + 2 + 2 + 2 + 2Wh... 阅读全文

摘要： 题目链接原题：It is possible to write five as a sum in exactly six different ways:4 + 13 + 23 + 1 + 12 + 2 + 12 + 1 + 1 + 11 + 1 + 1 + 1 + 1How many differen... 阅读全文

摘要： 筛选法求素数这里说了常见的素数的求法但是，当求很多素数的时候就不合理了，每个数都有遍历今天发现这个筛选法很不错。求limit内的所有素数维基百科链接V1.0步骤：1：从2开始2:2是素数，去除2的倍数的数3:下一个数是3,则3是素数，去除所以3的倍数的数4：下一个数是5，则5是素数，去除是5的倍数的... 阅读全文