General term formula of sequence 1 37 15 31 63 127

General term formula of sequence 1 37 15 31 63 127

The nth power of 2 minus 1

What is the nth number of 1,3,5,7,15,31? What is the nth number of 1,2,4,8,16,32?

From the second sequence
1 2 4 8 16 32 corresponds to the 0 th power of 2, the 1 th power of 2, the 2 th power of 2, the 3 th power of 2 and the 4 th power of 2 respectively
All nth numbers should be (n-1) power of 2

Find the rules: 1, 3, 7, 15, 31 What is the 100th number?

Its rule is to subtract 1 from the nth power of 2
That is: 2 ^ n-1, the 100th number is: the 100th power of 2 minus 1

1 3 5 7 15 31 () find the law

This is the civil service examination question, very impressive
Let me explain that 15 is the combination of 1 and 5 in the four digits of 1, 3, 5 and 7
31 is the combination of 3 and 1 in the four digit number 1 3 5 7
And then the number is 57, probably 53
If it is 53, the number after it should be the combination of 3 and 7 in 1 3 5 7, that is, 37 is less than 53, so 53 is excluded
That's 57, followed by 75