n=k时
(4^2k+1)+(3^k+2)
能被13整除
n=k+1时
(4^2k+3)+(3^k+3)
=4^2(4^2k+1)+3(3^k+2)
=16(4^2k+1)+3(3^k+2)
=13(4^2k+1)+3(4^2k+1)+3(3^k+2)
=13(4^2k+1)+3[(4^2k+1)+(3^k+2)]
4^2k+1是整数,所以13(4^2k+1)能被13整除
(4^2k+1)+(3^k+2)能被13整除,所以3[(4^2k+1)+(3^k+2)]也能被13整除
所以13(4^2k+1)+3[(4^2k+1)+(3^k+2)]也能被13整除