P141
projecteuler.net

Square Progressive Numbers

ℹ️Published on Saturday, 17th February 2007, 05:00 am; Solved by 4488;
Difficulty rating: 60%

A positive integer, $n$, is divided by $d$ and the quotient and remainder are $q$ and $r$ respectively. In addition $d$, $q$, and $r$ are consecutive positive integer terms in a geometric sequence, but not necessarily in that order.

For example, $58$ divided by $6$ has quotient $9$ and remainder $4$. It can also be seen that $4, 6, 9$ are consecutive terms in a geometric sequence (common ratio $3/2$).
We will call such numbers, $n$, progressive.

Some progressive numbers, such as $9$ and $10404 = 102^2$, happen to also be perfect squares.
The sum of all progressive perfect squares below one hundred thousand is $124657$.

Find the sum of all progressive perfect squares below one trillion ($10^{12}$).



Soluzione

Last modified: May 01, 2025. Website built with Franklin.jl and the lovely Julia programming language.