三个三个的数余2个,4个4个的数余3,5个5个的数余4个,6个6个的数余5个也就是是3,4,5,6,的倍数少1,又是7的倍数3,4,5,6的倍数是60,120,少1就是59或1197的倍数7,14,21,28,35,42,49,56,63,70,77,84,91,98,105,112,119……...