Is Pi Normal?

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Open Question

It is not known whether $\pi$ (pi) is normal.


Historical Note

The question as to the normality or not of $\pi$ (pi) arose when Augustus De Morgan investigated the $707$-digit approximation to $\pi$ that had been published by William Shanks in $1853$.

De Morgan noticed that the digit $7$ occurred less frequently than the other digits: only $44$ times against the expected $61$.

He determined that the probability of this low frequency was $45$ to $1$ against.

However, as discovered by D.F. Ferguson in around $1945$, Shanks had made a mistake in the $528$th digit. The correct calculation did not show that bias against $7$.


Since that time, all tests for normality that have been done on all known digits of $\pi$ have shown no suggestion that $\pi$ is not normal.

Work continues.


Sources