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Comments on Droppable Square numbers

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Droppable Square numbers Question

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A number $\large X$ is defined to be a Droppable Square number if the ordinary base-10 representation of $\large X^2$ can be formed by inserting the digit $\large 2$ anywhere in the base-10 representation of $\large X$, even at the beginning or end of $\large X.$

Rearranging the digits of $\large X$ at any time is not allowed.


$\large 11$ is a Droppable Square number because $\large 11^2 \ = \ 121$ can be formed by inserting the digit $\large 2$ into the middle of $\large 11$ to form $\large 121.$

$\large 5$ is also a Droppable Square number because $\large 5^2 \ = \ 25$ can be formed by inserting the digit $\large 2$ at the beginning of $\large 5$ to form $\large 25.$


Find another Droppable Square number.


History

2 comment threads

[SPOILERS] Oh that's very clever. I see what you did there. :-) (13 comments)
Spoiler thread (3 comments)
Spoiler thread
trichoplax‭ wrote 4 months ago

I'm not sure if this is a spoiler so I've made the title of the thread a warning.

Is a Droppable Square number required to be an integer, or can it have a decimal point with numbers to the right too?

They need not be integers.

System‭ wrote 4 months ago

Thread renamed from "Possible spoiler" to "Spoiler thread" by trichoplax‭