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Totient Trial (Posted on 2016-10-24) Difficulty: 3 of 5
It is observed that Φ(1)=1 and, Φ(2)=1, where Φ(x) denotes Euler's totient function.
So for x=1, it is trivially observed that each of Φ(x) and Φ(x+1) is a perfect square.

(A) What is the next positive integer value of x such that each of Φ(x) and Φ(x+1) is a perfect square?

(B) What is the value of x with 2000 ≤ x ≤ 2100 such that each of Φ(x) and Φ(x+1) is a perfect square?

  Submitted by K Sengupta    
Rating: 5.0000 (1 votes)
Solution: (Hide)
x  x+1  totient function values
1    2        1    1
125   126     100 36
504   505     144 400
512   513     256 324
513   514     324 256
629   630     576 144
679   680     576 256
1358 1359     576 900
1728 1729     576 1296
1970 1971     784 1296
2047 2048     1936 1024
2834 2835     1296 1296
For an explanation, refer to:
• The computer program assisted solution submitted by Charlie in this location.
• The solution submitted by Jer in this location.

Comments: ( You must be logged in to post comments.)
  Subject Author Date
Solutioncomputer solutionCharlie2016-10-24 19:16:26
SolutionMy wayJer2016-10-24 13:39:57
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