阿债的方寸天地

昨天在地铁上，突然想到当天是21号，星期一。打开手机看了一下，2001年1月1号正好是星期一。于是就有一个有趣的问题：那么21世纪中(2001-2100)，每个月的1号，同时又是星期一的日子大约有多少天：A. 50 B. 150 C. 350 D. 550当然，答案是后来设计的。当时我考虑这个问题，每个月1号是星期一，具有随机性。按概率算，整个世纪共有100*12个1号，1/7是星...

有个很有意思的网站 ProjectEuler.net ，提出了200多道数学问题，要求读者用计算机求解，不限制所用的计算机语言。（2008年11月）试着用Python做了几道，挺有意思的。[list][*] Add all the natural numbers below one thousand that are multiples of 3 or 5.[*] Find t...

[b]E002[/b][i]Each new term in the Fibonacci sequence is generated by adding the previous two terms. By starting with 1 and 2, the first 10 terms will be: 1, 2, 3, 5, 8, 13, 21, 34, 55, 89, ....

[b]E003[/b][i]The prime factors of 13195 are 5, 7, 13 and 29.What is the largest prime factor of the number 600851475143 ?求600851475143的最大质因子。[/i]今天重写了求素数的方法[code="python"]# -*- codi...

[b]E004[/b][i]A palindromic number reads the same both ways. The largest palindrome made from the product of two 2-digit numbers is 9009 = 91 99.Find the largest palindrome made from the produc...

[b]E005[/b][i]2520 is the smallest number that can be divided by each of the numbers from 1 to 10 without any remainder.What is the smallest number that is evenly divisible by all of the numbers...