牛生牛的问题 说是：有一个农场有一头成年母牛，每三个月后一头小牛， 小牛一年后长大，长大后每三个月又可以生一头小牛， 如此循环，问10年后农场一共有多少牛?-The issue of beef cattle Health That is: there is a farm there is an adult cow, a calf every three months,     One year after the calf grew u