2^(3n+4)×5^(n-1)+3^(2n+1):31
16×2^3n×5^(n-1)+3×3^2n=
16×8^n×5^(n-1)+3×9^n=16/5×40^n+3×9^n=
16/5(31+9)^n+3×(40-31)^n=
16/5(M31+9^n)+3×(40^n-M31)=
16/5M31+(16/5)×9^n+3×(31+9)^n-M31=
16/5M31+(16/5)×9^n+3×(M31+9^n)-M31=
M31(16/5+3-1)+9^n(16/5+3)=
M31(16/5+3-1)+9^n×(16+15)/5=
M31+9^n×31/5=M31+M31=M31
