If we observe the law of 1:2,12:4,13:8, then the fifth number is () and the nth number is ()

If we observe the law of 1:2,12:4,13:8, then the fifth number is () and the nth number is ()

One and one in two
Two and a quarter
Three and one in eight
.
According to the above data, it can be concluded that the general formula of this sequence is
an=n+1/2^n
So find the fifth number, put five generations in, and you'll get
A5 = 5 + 1 / 32 = 5 and 1 / 32
The nth number = n + 1 / 2 ^ n (n = 1,2,3,...) )
Then the fifth number is (5 and 1 / 32), and the nth number is (n + 1 / 2 ^ n, that is, 1 / N of the nth power of N and 2)