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Fibonacci but with Subtraction still stays Positive (Posted on 2023-02-15) Difficulty: 3 of 5
Let D[n] be a sequence whose values are recursively related by D[n] = D[n-2] - D[n-1].

D[1] is fixed to be equal to 1. Most choices of D[2] will result in a sequence which eventually has some n such that D[n] is negative.

What is the set of values for D[2] exist such that all terms of D[n] are positive?

See The Solution Submitted by Brian Smith    
Rating: 4.0000 (1 votes)

Comments: ( Back to comment list | You must be logged in to post comments.)
Some Thoughts Puzzle Thoughts Comment 3 of 3 |
When,  D[2] = (-1+sqrt(5))/2 , then all the terms of D(n) are positive.

Edited on February 22, 2023, 2:26 am
  Posted by K Sengupta on 2023-02-22 02:25:00

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