1. The problem statement, all variables and given/known data I am trying to solve this problem and need help with one aspect. 2. Relevant equations sequence: 0,-1,0,1 -- repeated. 3. The attempt at a solution How do I make every 4th term of the sequence a negative number? for instance i have: (1 + (-1)^n)/2 but i don't know how to alternative the -1 term in.