Metamath Proof Explorer


Theorem nnpw2blenfzo

Description: A positive integer is between 2 to the power of the binary length of the integer minus 1, and 2 to the power of the binary length of the integer. (Contributed by AV, 2-Jun-2020)

Ref Expression
Assertion nnpw2blenfzo NN2#b N 1 ..^ 2#b N

Proof

Step Hyp Ref Expression
1 nnpw2blen N2#b N 1 N N<2#b N
2 nnz NN
3 2z 2
4 blennnelnn N#b N
5 nnm1nn0 #b N #b N10
6 4 5 syl N#b N 1 0
7 zexpcl 2#b N 1 0 2#b N1
8 3 6 7 sylancr N2#b N 1
9 4 nnnn0d N#b N 0
10 zexpcl 2#b N 0 2#b N
11 3 9 10 sylancr N2#b N
12 elfzo N2#b N 1 2#b N N2#b N1..^2#b N2#b N1NN<2#b N
13 2 8 11 12 syl3anc NN2#b N 1 ..^ 2#b N 2#b N1NN<2#b N
14 1 13 mpbird NN2#b N 1 ..^ 2#b N