`(2^(n+2) -1)/((n+1)(n+2))``(2^(n+2)+n+1)/((n+1)(n+2))``(2^(n+2)-n-3)/((n+1)(n+2))``(2^(n+1)+n+3)/((n+1)(n+2))`
Your experience on this site will be improved by allowing cookies. Read Cookie Policy