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Two Geometric Series (Posted on 2003-07-14)

Find a geometric series of 3 or more positive integers, starting with 1, such that its sum is a perfect square.

See if you can find another such series.

See The Solution Submitted by Brian Smith

Rating: 3.6667 (6 votes)

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Thoughts on the Problem

Comment 11 of 11 |

Two solutions are:

1+3+3^3+3^3+3^4 = 11^2, and

1+7+7^2+7^3 = 20^2

The lucid corresponence between DJ and exoticorn proves beyond doubt that these are the possible solutions, if it is stipulated in the puzzle that the perfect square can have at most 37 digits.

Edited on August 30, 2022, 2:41 am

Posted by K Sengupta on 2022-08-29 22:51:31

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