When we write , we refer to natural logarithm. Let be an integer, be a real number and be the th prime. Let . holds for since and hold. Therefore, the following inequality holds for where holds.
We consider the following inequality.
In the meantime,
holds by Firoozbakht's conjecture holds for . And the inequality (3) holds for . If the following inequality holds, then the inequality (2) holds.
Let be the big notation. This inequality holds for greater than a certain value since holds and the divergence speed of the right-hand side is greater than the one of the left-hand side . Let be as follows.
It is confirmed that holds for and the inequalities (2) and (4) hold for . Let be as follows.
It is confirmed that holds for and the inequality (2) holds for . Let .
It is confirmed that holds for . From the above, it is proved that holds for by the inequalities (1) and (2) and holds for . (Q.E.D.)