HDU 1492 The number of divisors(约数) about Humble Numbers
ProblemDescriptionAnumberwhoseonlyprimefactorsare2,3,5or7iscalledahumblenumber.Thesequence1,2,3,4,5,6,7,8,9,10,12,14,15,16,18,20,21,24,25,27,...showsthefirst20humblenumbers.Nowgivenahumblenumber,pleas