Answer:
[tex]\large\boxed{f(n)=2\cdot f(n-1)+1}[/tex]
Step-by-step explanation:
[tex]f(1)=5\\\\f(2)=11=2\cdot5+1=2\cdoy f(1)+1\\\\f(3)=23=2\cdot11+1=2\cdot f(2)+1\\\\f(4)=47=2\cdot23+1=2\cdot f(3)+1\\\\f(5)=95=2\cdot47+1=2\cdot f(4)+1\\\vdots\\f(n)=2\cdot f(n-1)+1[/tex]
