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Two Geometric Series (Posted on 2003-07-14) Difficulty: 2 of 5
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.

  Submitted by Brian Smith    
Rating: 3.6667 (6 votes)
Solution: (Hide)
Two such series 1,3,9,27,81 and 1,7,49,343 are solutions.

There are others.

1+3+3^2+3^3+3^4=121=11^2 and 1+7+7^2+7^3=400=20^2

Comments: ( You must be logged in to post comments.)
  Subject Author Date
answerK Sengupta2007-11-08 09:53:58
re(2): Programming SolutionDJ2003-07-15 05:41:05
re: Programming Solutionexoticorn2003-07-14 22:41:33
SolutionProgramming SolutionDJ2003-07-14 18:10:12
after some quick programming...exoticorn2003-07-14 06:58:54
Hints/TipsHalfway thereBryan2003-07-14 06:51:51
Solution2 solutionsexoticorn2003-07-14 06:48:05
SolutionKyph2003-07-14 06:46:14
Some ThoughtsStartersDJ2003-07-14 06:43:22
The Cheap SolutionKyph2003-07-14 06:37:02
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