trig
posted by lindsey on .
find all sets of three consecutive odd integers whose sum is greater than 54 and less than 63

The sum of three consecutive odd integers is
S(n)=(n2) + n + (n+2) = 3n
So 54<S(n)<63, or
54 < 3n < 63
Divide all by 3 to get
18 < n < 21
Solve for all valid (integer) value of n.
Each value of n relates to the set of integers {n2, n, n+2} that satisfies the specified requirements. 
how do you get n2, n, n+2 I keep getting n, n+2 and n+4?