Smallest Penholodigital Square/Mistake

Source Work

1986: David Wells: Curious and Interesting Numbers:

The Dictionary

$11,826$

1997: David Wells: Curious and Interesting Numbers (2nd ed.):

The Dictionary

$11,826$

Mistake

$11,826^2$ is the smallest pandigital square. It was first noted by John Hill in $1727$, who thought it was the only pandigital square.

The book in which John Hill called attention to this number actually appeared in $1716$.

It was called Arithmetick, Both in the Theory and Practice, and appeared in a number of editions, one of which may well have been published in $1727$. Research is ongoing as to the exact number of editions, and their dates.

Note that in this context pandigital actually means penholodigital: that is, using all the digits except $0$.

Sources

• 1986: David Wells: Curious and Interesting Numbers ... (previous) ... (next): $11,826$
• 1997: David Wells: Curious and Interesting Numbers (2nd ed.) ... (previous) ... (next): $11,826$