2013年5月17日

摘要： 求拉兹序列的最大链长：The following iterative sequence is defined for the set of positive integers:nn/2 (nis even)n3n+ 1 (nis odd)Using the rule above and starting with 13, we generate the following sequence:134020105168421It can be seen that this sequence (starting at 13 and finishing at 1) contains 10 terms. 阅读全文

摘要： 就是大数相加，100个50位的数相加，取和的前10位Work out the first ten digits of the sum of the following one-hundred 50-digit numbers.3710728753390210279879799822083759024651013574025046376937677490009712648124896970078050417018260538743249861995247410594742333095130581237266173096299194221336357416157252243056330181107 阅读全文

摘要： 求第一个有500个除数因子的三角数，具体题目见原文：The sequence of triangle numbers is generated by adding the natural numbers. So the 7thtriangle number would be 1 + 2 + 3 + 4 + 5 + 6 + 7 = 28. The first ten terms would be:1, 3, 6, 10, 15, 21, 28, 36, 45, 55, ...Let us list the factors of the first seven triangle numbers:1 阅读全文