MathDB

Let an integer

n > 3

. Denote the set T\equal{}\{1,2, \ldots,n\}. A subset S of T is called wanting set if S has the property: There exists a positive integer

c

which is not greater than

\frac {n}{2}

such that |s_1 \minus{} s_2|\ne c for every pairs of arbitrary elements

s_1,s_2\in S

. How many does a wanting set have at most are there ?

Problem Statement