Question

Consider a list of numbers between 1 and n.
How many of them are not 3 times another number on the list ?

Answer 1

numbers except in form 3k

Answer 2

so how will u express it??

Answer 3

[ ] is the greatest integer function

Answer 4

forget those

Answer 5

n-[n/3]

Answer 6

n - round up to lower integer[n/3]

Answer 7

greatest integer function,
if n is a real number, [n] is the greatest integer less than n
we express the fractional part as{n}
so, n=[n]+{n}