f(1)=3f(1)=3
f(n)=-2f(n-1)+1f(n)=−2f(n−1)+1
f(2)=-2f(1)+1f(2)=−2f(1)+1
f(2)=-2(3)+1=-6+2=-5f(2)=−2(3)+1=−6+2=−5
f(3)=-2f(2)+1f(3)=−2f(2)+1
f(3)=-2(-5)+1f(3)=−2(−5)+1
f(3)=11f(3)=11
f(4)=-2(f(3))+1f(4)=−2(f(3))+1
f(4)=-2(11)+1f(4)=−2(11)+1
f(4)=-22+1=-21f(4)=−22+1=−21
f(5)=-2(f(4))+1f(5)=−2(f(4))+1
f(5)=-2(-21)+1f(5)=−2(−21)+1
f(5)=42+1f(5)=42+1
f(5)=43f(5)=43